Engine misfiring

Good morning,

I attached the initialization of the throttle body for you.

https://www.2carpros.com/articles/how-a-throttle-body-works

Are there any issues that lead you to do this procedure?

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

Roy

PERFORM INITIALIZATION
NOTICE:

Be sure to perform this procedure after reassembling the throttle body or removing and reinstalling any throttle body component.
Perform the following procedure after replacing the ECM, throttle body assembly or any throttle body components. The following procedure should also be performed if the throttle body is cleaned.
Be sure to perform this procedure after replacing the ECM and reconnecting the battery cable.
Disconnect the cable from the negative (-) battery terminal. Wait at least 60 seconds and reconnect the cable.
Turn the ignition switch to ON without operating the accelerator pedal.
NOTICE:

If the accelerator pedal is operated, perform the above steps again.

Connect the Techstream to the DLC3 and clear the DTCs . [ 2GR-FE ENGINE CONTROL: SFI SYSTEM: DTC CHECK / CLEAR ]
Start the engine and check that the MIL is not illuminated and that the idle speed is within the specified range when the A/C is switched off after the engine is warmed up.
Standard:


Condition Engine Idle Speed
A/C switched off 600 to 700 rpm

NOTICE:

Be sure to perform this step with all accessories off.
Make sure that the shift lever is in neutral.
Enter the following menus: Powertrain/ Engine / Data List/ Throttle Sensor Position. Fully depress the accelerator pedal and check that the value is 60% or more.
Perform a road test and confirm that there are no abnormalities.

Also need ignition coils wiring diagram. Getting weak spark on cylinder 1 and 3. Any help would be great. thanks!!!

Okay, I attached the wiring diagram for you of the ignition system.

https://www.2carpros.com/articles/how-to-check-wiring

Do you have any codes set in the system? If so, can you give those codes so I can help narrow the area of failure.

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

You will have a battery feed with the key on to the coil. Then the ECM will command it to fire based on the position of the crank sensor.

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works

Roy

Still getting codes p0301,p0303 and p0305. after installing new spark plugs, checked coils, injectors and vacuum. But there is some noise coming from that Head Cylinder.

Okay, I wish you would have told me about these codes in the beginning.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

I would start with a compression test to verify no internal engine issues.

https://www.2carpros.com/articles/how-to-test-engine-compression

The most common failure for the 300 code is fuel pressure you need to test the fuel pressure to be sure there is sufficient pressure to the injectors.

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

Roy

Will lack of fuel pressure cause noise in head cylinder ? But will do compression test after work. Plus i think i need adapter for fuel check.

Can you upload a video of the noise from the head?

Keep me updated.

Roy

Turned out to be no compression on cylinder on #1 (valve spring broken).Waiting on special socket for head cylinder bolts to arrive.. Can you provide timing procedure on on chains? Thanks very much in advance !!!

You are welcome.

Always glad to help.

Roy

2008 Toyota Sienna - garage could not get it to repeat and said it was water in the fuel line.

My wife was driving her 2008 Toyota Sienna down the highway yesterday. She was about 40 minutes into the trip, when the Check Engine light started to flash, about 20 seconds later, the VSC light went on and the car was shaking uncontrollably. She pulled off and I went to check the car. I started it and took it to a local garage. They pulled the codes and said that it had all 6 cylinders misfire and it had overheated.

The shop tried all day to recreate the issue and it never did. I drove it back from the shop (Another hour or so with traffic with no issues)...Can anyone explain what that issue is and how I can avoid issues with this in the future. The garage said it may have been "Water in the fuel line" but I want to be sure. Thank you.

I have never seen water in the fuel to cause over heating.I have seen missfires engine justs dies and wont start etc but not overheating.Why did they say it overheated?

He gave no reason for the overheat and said it may have been an old code, as I have never seen it overheat. My main concern is the misfiring cylinders and the lack of "cause", as my wife tends to take long trips alone and I bought this van because of reliability.

Those wouldnt be old codes because when the check engine light flashes that means there is a major missfire that can damage the cat.So is there a list of the codes it had the exact code numbers not code descriptions?So it hasnt happened since?Also how many miles ago did it happen?It wouldnt hurt to get a good fuel drier and add that to the tank.I have seen water in the gas cause very phatom running issues.

It was likely 60 miles ago...and not has not happened again and hopefully never again. The mechanic did say when he was inspecting the engine at first that, I believe it was an ignition wire was "loose" and he pushed it down so it had a better connection, could this have caused the 6 cylinder misfire??

That has one coil for each spark plug with a connector going to it.so i dont see how one could set codes for every cylinder missfiring.I would get some good fuel drier i recommend the bg products brand i have used it in the past.It works very good you can find it on ebay or call around to shops and see if they carry bg products.Iam not sure what happened i wasnt there to see it after it happened see the actual codes etc.So did it act up for the people that looked at the car?

Recently replaced knock sensor, now I'm getting multiple misfire as well as misfire in number 6. I'm at a loss, any idea what would cause it aside from obvious? I already tried obvious fixes.

It never acted up again for the people who tried identifying the issue, the codes were P0300 P0301 P0302 P0303 P0304 P0305 P0306, I don't have the overheat code.

Good morning,

What is the obvious repairs you did?

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

The first thing I would do is a fuel pressure test to be sure there is sufficient fuel to the injectors.

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

I would also do a compression test on at least the cylinder listed to be sure there is no internal issues with the motor.

https://www.2carpros.com/articles/how-to-test-engine-compression

Roy

I would try the fuel drier fuel would effect all the cylinders and could be very sparatic.

My wife just had the same problem with her 2008Sienna. Filled tank with gas and drove it 60 miles on highway and had identical situation. She had it towed to a Toyota dealer in Superior who said all codes showed misfire but they could not replicate problem. His guess was bad gas. Have now driven it another 50+ miles and no problem. Is this a common sienna problem? Is it safe to drive?

Any car can get water in the fuel or a bad tank of gas which from the symptoms sounds like that's what happened.

When all cylinders misfire...it the air mass sensor that doesn't detect air coming in the engine cause misfire...not enuff oxygen...it doesn't happen at all like that...give a try to replace air filter, pcv valve need to be replaced and air mass sensor replaced and use obd2 scanner to erase code and see what happen...it wouldn't come back on

had check engine light come on auto zone diagnosis was misfire cylinder 1 &6 and random misfire have replaced plugs wires all coil packs and #6 injector still surges and runs poor any idea

Engine running rough or misfiring can be cause by the following:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

1.Defective spark plugs
2.Inadequate spark/coil,defective spark plug wire.
3.Lack of compression
4.False air leakage.
5.Faulty fuel injectors.
6.Insufficient fuel pressure.
7.Contaminated fuel.
8.EGR valve that is leaking.
9.Oxygen sensors.
10.Throttle position sensor.
11.Manifold absolute pressure sensor
12.Mass Airflow Sensor
13.Idle air control valve

Note: If it doesn't apply disregard it-

do a compression test and check if coils firing injectors pulsing

I have a 2000 Toyota Sienna XLE which is having some problems. The engine seems to be misfiring and the codes P0300 P0304 P0306

I replaced the plugs and the fuel filter so far. Should I replace the plug wires next? It seems like they will be hard to change at the back side near the firewall. Any suggestions would be helpful. Thanks

You should replace the spark plug wires when you replace the spark plugs. Do you know if the intake plentum must be removed to replace the wires by the firewall?

I had the water pump, timing belt and seals replaced around 91,00. I do regular oil changes, and have noticed some oil drops on floor over last year(though oil level is always fine).

Car was driving fine till yesterday. Today wife complained (after driving five miles) about burning smell and steering wheel was vibrating. Check engine lights came on.

I checked codes - P0300, P0302, P0305. I found the coolant tank was almost empty(some coolant at bottom). I found the engine compartment was sprayed with white salt type liquid and dried (I have photos).

I reset codes. Refilled coolant. I started the engine after refilling coolant it runs fine, but the steering wheel vibrates when engine is in "D". Also the panel light for "D" does not illuminate (P and R lights do illuminate).

Need help to figure out if it is a radiator issue or spark plug/coil issue. I also have some oil leaking from the engine that was already present due to age of the car.

have system pressure checked for leaks, but with the codes you have it may be a bad head gasket. and it may have sprayed coolant on to the transmission selector and causing your illumination problem.

here is a link to a pressure test video

http://youtu.be/W8kra65m15c

Thanks HMAC300. I will try to get the system pressure tested today.
Some more information. I started the car and got it to operating temperature. The codes returned (P0300, P0302, P0305). No visible leak except for a few drop of coolant dripping below radiator. The engine and steering wheel vibrates when put in gear(R/D) but not in P or N. I touched the inlet and outlet radiator hoses both are hot with car just parked in garage. Sounds like radiator issue ?

I am going to do coil swap to rule our coils/wires. Will put in the fuel injector cleaner to clear nozzles.

Any other suggestions ?

Pressure tested using Harbor Feight Radiator Compression Tester. Radiator has a leak at top inlet pipe. Coil swapping to be done next.

Just to add to this one a little, a vehicle may cause misfiring codes when its overheating. I would fix the coolant issue first before diving into the misfiring problem just in case it sorts itself out. If the coolant issue is fixed and misfire codes are still present, proceed with coil swapping to see it the misfire follows the coils. Inspect the spark plugs as well while you're in there and make sure they aren't worn down where the spark plug gap is too big. Best of luck.

Thanks all for the help. After researching and getting help from posters like you, I was able to sort out the problem (hopefully..)
1. Problem#1 Busted radiator - Radiator inlet was leaking as detected using the pressure test. Replaced with new radiator. Drained/flushed/refilled coolant.
2. Problem#2 Engine Misfire cyl #2 & 5. Turned out to be bad ignition coil. It was my mistake earlier to have not labelled the coils properly when swapping. When I did the spark test - it came out clear.
3. Problem #3 Exhaust manifold(Upper catalytic converter) was turning red hot due to unburnt fuel getting there. This was due to Problem #2 and so once that was fixed, it corrected.

I learnt a lot in the process and am thankful to the community for tips. Youtube is also great help.

Misfire #1 cylender. During ideal and acceleration. Comes and goes. Might be weather related misfire less during cooler low humidity days. Temperature under 70 degrees less misfire occurrence.

check fuel pressure with a gauge and for vacuum leaks first then compression

I'm glad we could help you, please use 2Carpros.com anytime we are happy to be of assistance.

Forgot to mention Scan error codes P0300 & P0301. I know P0300 is random misfire & 301 is misfire cyl#1.
It acts more like an occasional bad connection. ("on again/off again" misfire)
If it was fuel pressure problem would it only affect one cylinder? And if it did, would it then be a injector problem?

no it still cold be fuel pressure due to being low as well as vacuum leak. it also could be injector but check what I said first.

Will do, will report back, Thanks!