Hesitation and high Idle after cold start

1997 TOYOTA CAMRY
157,000 MILES • 3.0L • 6 CYL • 2WD • AUTOMATIC
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JAY_SANCHEZZ15
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Hi there, My car listed above LE V6
156,000 miles - hesitates when I am in traffic.
For example, in stop and go traffic I will come
to a stop slowly, and try to accelerate but
there is about a 1 second delay when I press
the pedal and the car goes. This doesn’t
usually occur at high speeds just low speeds.

Should also mention that when I turn on the
car on a cold start (it’s 80*F outside), it idles
at about 1,800 rpms. It doesn’t settle lower
than 1k rpms until I put it in gear or wait a
long time (5min maybe?) If I don’t wait for the
car to settle to 1k rpm, and I choose to put it
in drive, the idle drops from 1,800 to about 800rpm (normal I think?) and the car will “walk”
at about 5mph which seems and feels rather
fast because I am not pressing the gas, and
as soon as I do it will shift into 2nd gear
because it’s already traveling fast. It also is difficult to stop with brakes after cold start (because its "walking" fast)

Car has no CEL codes
Car passes emission test with my OBDII
scanner(Blue Driver)
Recent Maintenance done:
New Battery Replaced Spark Plugs and rear
wire set. (NGK)
New Air Filter
New Fuel Filter
Changed Transmission Filter (not flushed just
drained because ATF was black)
New Engine Coolant Temperature Sensor
Tried to clean IAC with throttle cleaner
Cleaned MAF Sensor with MAF Sensor
cleaner.

Could this be a bad throttle position sensor or Oxygen Sensor?
Any help would be appreciated as I am a
college student and don’t have much money
to throw into parts.
Jun 28, 2019 at 11:33 AM
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STRAILER
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It is important the IAC is clean because it is hindered easier with gunk. Here is a video of the job being done:

https://youtu.be/XMB16Gg-qNg

Please run down this guide and report back.
Jun 29, 2019 at 7:40 PM
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JAY_SANCHEZZ15
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Thank you for your reply Ken.
Is it worth cleaning the IAC valve or replacing it entirely given the amount of miles on the car?
Does the IAC motor wear out or is it simply carbon buildup that keeps it from opening and closing?
My reasoning is that I could take it apart clean it, but if the motor is worn out then I’d still have to replace it.
Jun 30, 2019 at 3:26 PM
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STRAILER
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It is an electromagnet driven valve (no motor) they don't wear out just get dirty. Let me know what you find.
Jul 1, 2019 at 11:07 AM
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JAY_SANCHEZZ15
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I replaced the Idle Air Control Valve over the weekend with a new part from AutoZone. They were doing a sale for the 4th of July so I got it pretty cheap. I know cleaning was mentioned, but I found it rather difficult to clean the smaller areas deep in the valve.

Anyway, I started up the car and have yet to see any signs of improvement during cold start. Still idles high, around 1,800 rpm's and stays there unless I wait a while or put it in gear.
I am assuming that the car needs to relearn the idle with the new IAC, so I will take it on a long drive tonight.
Any suggestions on further steps?
Jul 8, 2019 at 8:00 AM
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STRAILER
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When you replace the valve did you service the throttle bore? Yes, it does need to relearn which a long drive will help achieve. Here is a guide to help with the throttle service:

https://www.2carpros.com/articles/throttle-actuator-service

Please run down this guide and report back.
Jul 8, 2019 at 10:49 AM
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JAY_SANCHEZZ15
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Yes, I removed the throttle bore and made sure it was as clean as possible. I used carburetor cleaner to do this. I also took a toothbrush to make sure I was getting into the area where the throttle plate rotates, took it to the butterfly, and the intake manifold (the plate seems to close all the way and open with no issues). The throttle bore is practically spotless, with no thick amounts of carbon. I also cleaned a little bit inside the intake manifold, as I noticed it had a lot of carbon build up. I just used the toothbrush and scrubbed it down best I could.

How long of a drive are we talking? I am assuming a long drive with various speeds? IE> highway and city driving
Jul 8, 2019 at 1:57 PM
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STRAILER
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It should take about five miles to reset, around town should do it. Make sure there are no vacuum leaks.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please run down this guide and report back.
Jul 9, 2019 at 9:34 AM
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JAY_SANCHEZZ15
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Haven’t checked for vacuum leaks, but wanted to update after driving car for a while. The car still idles high at cold start, and ‘walks’ fast. I have found that the car does not shift properly into third gear, when the car is cold. It reaches high rpm's and does not shift past about 20 mph, so it stays in the second gear. However, if I let the car reach operating temperature, it runs great. I’ll check for vacuum leaks this weekend.
Jul 11, 2019 at 8:07 AM
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STRAILER
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It sounds like you may have an engine coolant temperature sensor that needs to be replaced. When this sensor gets off slightly it will not give a code but it will cause engine run-ability problems. There are two of them I would change them both.
Jul 11, 2019 at 10:43 AM
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JAY_SANCHEZZ15
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Do you happen to have a coolant temperature sensor diagram/location for the 1997 Toyota Camry LE V6 model? The diagram shown is for a CE model. I have replaced one (Duralast from AutoZone) near the radiator cap when I made the original post.
Jul 11, 2019 at 4:14 PM
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JAY_SANCHEZZ15
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No vacuum leaks as far as I know. I followed the article sent. Sprayed good amount of carburetor cleaner to throttle bore, IAC gasket, brake booster, EVAP canister and valves, and intake manifold. I also sprayed as many of the vacuum hoses I could find, along and at the ends. They all look in good shape, with no significant idle increase as I sprayed. I used my phone to record the idle. No change.
Jul 11, 2019 at 4:41 PM
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The diagrams are the same for LE CE are they not there or? Can you please shoot a quick video with your phone so we can see what's going on, that would be great. You can upload it here with your response.
Jul 13, 2019 at 11:29 AM
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JAY_SANCHEZZ15
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So the first thing I point to in the video is the one coolant temperature sensor I have changed out. The second thing/area I point to is where the diagram claims two other sensors would be. I find one that looks like the sensor, but I don’t believe it is because it has one wire coming out of it only.
Jul 14, 2019 at 2:57 PM
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Thanks for the video I checked again and found more information on the sensors here are the location below.
Jul 15, 2019 at 11:28 AM
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JAY_SANCHEZZ15
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According to everything I could find, the car only has one engine coolant temperature sensor, that I replaced already. O’Reilly website even claims there is only one (see picture). However, there is a coolant temperature sender that has one wire lead and it’s connected to the thermostat housing.

I do not think that this has anything to do with the high idle issue, but I may be wrong.
Jul 18, 2019 at 7:02 AM
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Lets change the two wire sensor. The one wire is for the fan.
Jul 18, 2019 at 9:33 AM
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JAY_SANCHEZZ15
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The Engine Coolant Temperature sensor, like the one listed in the O'rielly pic, was replaced less than 2 months ago now. I bought it from Autozone (Duralast limited lifetime).
Jul 18, 2019 at 11:57 AM
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Yep I would try an OEM sensor, but looking again just cleaning the MAF doesn't work most of the time I would try a new sensor as well. If the sensor is off slightly it wont create a code. Let me know
Jul 19, 2019 at 4:58 PM
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JAY_SANCHEZZ15
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So I took it to a mechanic and they could not find anything out of the ordinary. They mentioned that there was metal shavings at the bottom of the pan, which I believe is normal wear. I went ahead an changed the Throttle Position Sensor (TPS) with a new OEM part, and I feel better response when the car is warm. The issue of the transmission not shifting correctly when cold worries me more than the high idle and fast creep. I have also noticed during the cold starts that it uses a lot of gas, like my tank gets noticeably lower when I get to work after cold start.
Aug 2, 2019 at 7:43 AM
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Did we get the coolant sensors replaced with OEM units? I would start there because it still sounds like the coolant sensor issue. Lets try a CAN scan as well, these are becoming more popular because it does the entire car.

Here is a video:

https://youtu.be/InIlnsjOVFA

Lets clear and run the codes again as well.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.


Aug 2, 2019 at 11:54 AM
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JAY_SANCHEZZ15
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I don’t know what your level of experience is, but my Bluetooth scan tool analyzes short and long term fuel trim, perhaps it could be useful so I decided to post it. I don’t know how to read it but I’ll look into fuel trim and the OEM coolant sensor as well.
Aug 2, 2019 at 6:35 PM
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STRAILER
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Thanks for the video it looks like the long trim at 6.2 is showing us there is a problem it looks like you may have a fuel injectors that is going bad. I would remove the spark plugs and look for one that looks different from the rest. Let me know.
Aug 3, 2019 at 10:39 AM
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JAY_SANCHEZZ15
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Just to confirm, Bank 2 would be the side wherever the second cylinder is correct? On the 1MZ-FE engine that would be the front of the engine if I am assuming correctly.
Aug 3, 2019 at 11:54 AM
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JAY_SANCHEZZ15
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Idle (Cold Start) Fuel Trims.
Aug 3, 2019 at 12:08 PM
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JAY_SANCHEZZ15
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1,500 rpm fuel trim (car beginning to warm up). Car is in Park.
Aug 3, 2019 at 12:10 PM
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JAY_SANCHEZZ15
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2,500 rpms Fuel Trim (Car is almost at operating temp, Car is in park)
Aug 3, 2019 at 12:12 PM
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JAY_SANCHEZZ15
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Idle Fuel Trim Again (Car is practically at operating temperature. Car is in Park. This is after the 2,500 rpm test)
Aug 3, 2019 at 12:13 PM
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JAY_SANCHEZZ15
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I removed Bank 2 spark plugs (I think that’s bank 2). They all look the same. They do not smell like gas. They are not covered with oil. However, I noticed that the valve cover gasket may be starting to leak in the middle cylinder (cylinder 4). Can a leaking valve cover gasket cause a vacuum leak?

As for the fuel trims, it seems to me like there is a gasket vacuum leak? Perhaps intake manifold as it swells up when the car gets warm?

*Note* the first fuel trim video (the one that you told me to check the spark plugs) was me actually driving the car yesterday, the car was at operating temperature. I should have clarified.
Aug 3, 2019 at 12:19 PM
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STRAILER
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Those plugs look lean, can you get the other side out at least one so we can see the color? if the other side has color than the first side you remove has the bad injector. I would remove the injectors and test them.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Please run down this guide and report back.

Aug 5, 2019 at 9:08 AM
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JAY_SANCHEZZ15
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I have a small smoke machine and I ran smoke (burned mineral oil) through the vacuum lines by connecting it to the brake booster hose. This thing makes a bunch of smoke, has a compressor hooked up to it, and I could not find any noticeable vacuum leaks around the intake or exhaust manifold.

But, I found a small crack in a section of the air intake hoses. After replacing the hose, the Long Term Fuel Trim is around 3 now (was 6). So that helped a little. All Fuel trims are now within +/- 10

Still have the same issue -
My idle on cold start does not drop under 1000 rpm's unless I actually drive it around. Still creeps quite fast. Seems to consume a lot of fuel during the cold start. Engine takes about 2 seconds to start up.

I will be replacing the ECT with an OEM part as next steps.

As for the injectors I do not think that is the problem. I have no issues with acceleration. What could be happening to them that relates to the issue?
Aug 12, 2019 at 7:36 AM
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I would replace the MAF sensor with a new unit cleaning does not always work when they are to far gone. This would explain the white spark plugs as well. Here is a guide to help with diagrams below to show you on your car:

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

Check out the diagrams (below). Please let us know what happens.
Aug 12, 2019 at 11:50 AM
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JAY_SANCHEZZ15
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I have tried a different MAF Sensor and it did not change the idle of the car cold or warm. It was one that I pulled from the Junkyard (Denso and same part number), but my scan tool shows both of them giving the same values during live data.

I appreciate you keeping up with this Ken. I have gotten quite busy these last two weeks.

This weekend I plan on:
Removing the rear spark plugs and taking a picture of them for the fuel injectors.

Replacing the ECT with an OEM unit.

I also plan on smoke testing the car while it’s cold to see if smoke comes out of the gaskets or some other place.
(I did it on a warm engine last time)
Could it be possible for a vacuum leak from the brake booster. I connect my smoke machine to that hose so how could I check the booster for leaks?
Aug 14, 2019 at 3:39 PM
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STRAILER
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The steps you are talking are correct, if you pull the vacuum valve from the booster and you hear vacuum escape the booster is okay. Let me know what happens after the work.
Aug 15, 2019 at 10:29 AM
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JAY_SANCHEZZ15
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Rear 3 plugs, they seem to look the same as the front 3.
Aug 17, 2019 at 11:37 AM
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Those are lean as well. We should check fuel pressure. here is a guide to help us with the pressure requirements:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Fuel Pressure 44 to 50 psi

Have you replaced the fuel filter?

https://www.2carpros.com/articles/how-to-change-a-fuel-filter

Please run down these guides and report back.

Aug 18, 2019 at 11:58 AM
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JAY_SANCHEZZ15
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Update: OEM Coolant Temperature Sensor did not resolve issue. I think it takes the car less time to settle the idle upon cold start, but the difference is too insignificant.

Yes, I replaced the fuel filter about 2 months ago. Bought it from AutoZone.

As for the fuel pressure test, the 1MZ-FE 3.0 L engine in my car does not have a schrader valve to hook up a gauge to.

All I found was this article for the 2.2L Camry:

https://troubleshootmyvehicle.com/toyota/2.2L/how-to-test-the-fuel-pump-2#2

Basically they put in another banjo bolt with an adapter for the Schrader valve where the fuel filter banjo bolt is. Although the guide is for the 2.2 L engine, I have access to that same banjo bolt as well as another one at the fuel rail. Could this be an alternative way to test the fuel pressure?

Also, I could not locate a fuel pressure regulator. I believe it’s under the rear seat where the fuel pump is but I’m not sure.
I have attached pictures of both banjo bolts and a picture of my fuel pressure test kit.
Aug 19, 2019 at 5:01 PM
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Yep, this is what we need to test the fuel pressure. The fuel pressure regulator is under the rear seat. Check out the diagrams (below). Please let us know what happens.
Aug 20, 2019 at 9:38 AM
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JAY_SANCHEZZ15
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How would I go about checking/testing the fuel pressure regulator? It is attached to the fuel pump housing so there is no vacuum line to check for fuel drips like a regular one in the guide.

Would it be worth to inspect any fuses/relays first?
Aug 20, 2019 at 10:31 AM
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It would be difficult to test the unit one it is out of the car. When you turned the ignition switch on without cranking the engine over do you hear the fuel pump run for 5 seconds?
Aug 21, 2019 at 4:49 PM
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JAY_SANCHEZZ15
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No I do not hear any noise coming from the fuel pump. I took the seat off an had someone help me switch it to ON and no noise. Do all fuel pumps make that priming noise?
Aug 23, 2019 at 4:29 PM