Engine high idle?

try cleaning the throttle plate on both sides with choke cleaner first and the oblong hole where the idle air control is. there is no adjustment.if it still does it after that take the choke cleaner and spray around the inlet manifold by the head. if the idle picks up you need a new inlet gasket.

This guide can help us fix it.

https://www.2carpros.com/articles/engine-idles-too-high

Please run down this guide and report back.

I have a 98 Pontiac Grand Am with a 3.1 with 100K miles. It has been idling up recently and no matter what will not idle down until i turn it off several times. I replaced the MAP sensor (like a mechanic told me to do) and it seemed to help for a while, but it went back the the same prob. (Also the brakes are very hard to push when it is revved up...so i was thinking a vacuum leak...but have not found one) The other more annoying problem I am having with this car is it just dies going down the road. I have to pull over and turn the car off, then restart it. It usually restarts, but sometimes does not. No one knows what is wrong with it. I have four kids and cannot be stuck on the side of the road. I need help with this please!

[quote:694af8bd21="christi992"]I have a 98 Pontiac Grand Am with a 3.1 with 100K miles. It has been idling up recently and no matter what will not idle down until i turn it off several times. I replaced the MAP sensor (like a mechanic told me to do) and it seemed to help for a while, but it went back the the same prob. (Also the brakes are very hard to push when it is revved up...so i was thinking a vacuum leak...but have not found one) The other more annoying problem I am having with this car is it just dies going down the road. I have to pull over and turn the car off, then restart it. It usually restarts, but sometimes does not. No one knows what is wrong with it. I have four kids and cannot be stuck on the side of the road. I need help with this please![/quote:694af8bd21]
Hello
Do you have check engine light coming on?
Brake paddle very hard
check the vacuum supply to booster
If supply is good unplug the vacuum from the booster and seal the vacuum
start car check the idle
Good luck

The Check engine light is on. I have had it tested and it says misfire on number 3. It has been like this for a while. I have replaced plugs wires and coil pack.

[quote:baa8120505="christi992"]The Check engine light is on. I have had it tested and it says misfire on number 3. It has been like this for a while. I have replaced plugs wires and coil pack.[/quote:baa8120505]

Not every misfire is a spark problem
Check vacuum leaks injector engine compression

This problem started with the idle at 4,000rpm. I replaced the throttle control sensor which made no difference. I removed the throttle body, cleaned it out with carb cleaner, especially where the IAC comes in (I think that is where the main problem was). I checked vacuum lines. I replaced the gasket, changed the spark plugs, wires, air filter, and oil, but it is still idling from between 1,000 - 1,600. How do I get it to idle at 800rpm? Is there something else I can do. The check engine light is on, when it goes through the test, it pretty much says there is an issue, but not specific. Where should I look next? If there is a vaccum line that would most directly impact this, which one would it be? Thanks for your help guys!

You need to check all vacuum hoses for leakage and also clean out IACV and see what happens

When the engine is still cold, spray water on the intake manifold gasket(s) and vacuum hoses. Watch for any place where it gets sucked in or where it makes the engine slow down momentarily. You can also pinch off various vacuum hoses to see if one brings the idle speed down. If you find one, follow it to its branches, then pinch each one to follow it to the leak.

I have a 97 Grand Am that has a high rpm starting problem. What can I do to keep it from idling so high?

How high does it go? Do the rpm's go up and down while sitting? Has the check engine light come on?

Yes, the enine light was on; but recent repair(replacing idle air contol motor) reset codes(p0107, p0141, p0172, p0506)and engine light is now off. It goes to 3500 rpms, then calms down to 1000 rpms after putting in gear with foot on brake. This cycle must be repeated again; then it's normal until the car is turned off again. It happens when the car is hot or cold.

I have 1997 grand am gt with a 2.4L manual trans the car runs good at an idle get up to 55 mph while it has a load on it runs good when it levels off on straight away it starts bucking about 4or 5times before straightens out and continues to do it every time after you put a load on it any help would be appreciated Thanks

HAs the check engine light ever come on? Have you checked fuel pump pressure? Here is a how to if you need it:

https://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

Let me know what you find.

No the check engine light has never come on but a new fuel pump and fuel filter was installed about 4 months ago

If the fuel pressure is good, and there is no check engine light, there has to be a vacuum leak or the catylatic converter is starting to plug. Have those items been checked?

No, but I will check those things and see what i get

Let me know what you find.

I have been experiencing high RPM's that remain steady when I go 65-70 MPH and the RPM'S remain high until I let up off the gas a little. There is an exhaust leak in the car too.

Another thing that is happening is the car is slow to accelerate from a stop position. And the check engine light is on also.

have the car scanned to see what is causing the high rms. Also check around the exhaust leak to see if there is a wire touch or burnt . With reference to the exhaust leak I would have it repaired, If the engine is running the fumes can seep into the passenger cabin, and may be a hazard to your health.

I have a 1996 grand am 3.1. When you start it up it will idle just fine for a minute or two then it will idle up high and then idle really low and spit and sputter. To keep it from dying you have to keep your foor on the pedal. After you take off it will work itself out and will not act like that anymore, however if you shut it off for more than an hour it will do it again when you start it back up. I have replaced the map sensor, and the throttle control sensoe. I had it put back on the computer and it says the oxygen sensor had no activity even though its new as well. I got a good deal on the car and it runs really good after you get it going so I would love to know where to start..

clean the throttle plate with choke cleaner on both sides first as well as the iac hole. which O2 sensor has no activity you may have replaced the wrong one and is it due to a bad connection?

2.3 L Quad 4 Normally idles at 1000 rpm - Recently started a high idle from 1600 - 2000 rpm then gradually slows idle to 1100 - 1300 rpm - Had mechanic check with scanning tool and no faults detected - New plugs , air filter , etc. - Car otherwise runs fine with AC on or off . Problem is killing gas mileage - MPG at 15 - 16.
Any suggestions greatly appreciated .

Normally a high idle is caused by a vacuum leak. One concern is that the ECM should be setting an idle speed error.

I would check for vacuum leaks, and remove/clean the IAC and base.

Engine Performance problem
1995 Pontiac Grand Am 6 cyl Two Wheel Drive Automatic 259 km miles

Hi just a quick question my sisters car in the morning has a high ilde, only sometimes she tell me that it feels like its idling at 4-5000rpm. i think it might be the iac but not shure. im a ford tech and dont work on these cars ever can you help. thanks

You could remove and clean the IAC, but an idle that high (4-5K) is most likely a vacuum leak and a big one like a power brake booster line.

I would probably take a look at the car yourself, I really doubt it is 4-5K, and is most likely an IAC, since vacuum leaks don't fix themselves :) .

I have a 1995 pontiac grand am with the Quad 4 engine. When started it revs high, approx 2500 rpms. I was told this particular year, model was hard to pull codes because its not a full obd 2. I thought the TPS might be bad but changing that did not help. I hate to keep parts swapping but unless I can pull codes, I have not other choice. Would a bad MAP sensor or IAC cause it to rev that high and stay there?

Is Data Link Connector 12 or 16 pin? Suspect IAC causing problem remove and clean maybe carbon holding pentil open

Most of this particular year are OBD1 system with OBD2 connector and will not give flash code nor will they read with a generic code reader. They require a professional scan tool to access codes on this one year.

You may have a bad IAC ( idle air control) but try eliminating any vacuum leaks and cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.

Thanks for the advice. I had my father, whose car this is, disconnect the battery to reset the ecm and then run the car a little to get the new tps working properly. Now it runs like it should, just needed a reset and some time to get the new tps working. Thanks again

Let's hope so.

Engine Performance problem
1994 Pontiac Grand Am 6 cyl Front Wheel Drive Automatic

My son ran his car through a large puddle and it sucked in lots of water. We have changed the starter the plugs and mass air flow sensor, flow the oil a couple of times. It continues to idle high in the drive way and when drive it wants to take off and hold one speed ...Fast! Could it be the oxygen sensor or the IAC?

Could be the idle air control valve try cleaning out and see what happens


Too fast an idle speed. If an engine without computerized idle speed control is idling too fast and refuses to come down to a normal idle speed despite your best efforts to back off the carburetor idle speed screw or air bypass adjustment screw (fuel injection), air is getting past the throttle somewhere. Common leak paths include the carburetor and throttle body gaskets, carburetor insulator spacers, intake manifold gaskets, and of course, any of the engine's vacuum fittings, hoses and accessories. It is even possible that leaky O-rings around the fuel injectors are allowing air to leak past the seals. Another overlooked item can be a worn throttle shaft and a defective idle speed speed control motor/valve stuck in the extended (high idle speed) position/throttle position sensor. Also the throttle plate could be binding in its bore and kinked accelerator cable, coolant temperature sensor might not be operating properly misleading the computer that the engine is still cold and computer throwing fuel at it raising the idle speed.

I just had the thermostat replaced and now it chugs and idles hugh when it starts

Have you called shop and told them whats going on? May have left engine temperature sensor unplugged on rear of engine see if it is unplugged. may need to remove air cleaner to gain access.

Hey CINDY,

Yes that is near the TPS sensor maybe they bumped the connector and now it has a bad connection. Is the check engine light on?

Also they could have left off or not properly connected the air intake boot,, here are a couple of guides that will help you.

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

and

https://www.2carpros.com/articles/replace-an-air-intake-boot

Run some tests and get back to us so we can continue helping you.

Best, Ken

my car idles too high

Typical of a vacuum leak. Check the vacuum hoses for leaks and the intake manifold gaskets. When the engine is still cold and running, use a spray bottle to spray water on the gaskets. If you see it get sucked in and the engine slows down momentarily, you've found the leak.

Hello all. I have a 93 Grand AM with a 3.3 litre with a high idle. (2000-3000 RPM's hot or cold). I replaced the IAC with a known good one, cleaned the throttle body, the MAF, and the IAC passages in the throttle body and still have the same high idle. Checked for vacuum leaks with carb cleaner with none found. I have an OTC scan tool and have scanned some data and what seems weird is that the IAC counts stay at 110-120 whether in park or in gear at 1300 RPM's. I've heard the IAC counts should be down around 20-30 or so. The TPS scans ok between .27 and 4.0 from idle to wide open throttle. O2 sensor is switching back and forth OK too. I just got this car and have no troubleshooting or wiring diagrams. I'm thinking maybe some wiring issues between the IAC and PCM? I'm at a loss on this one! Any ideas?

DH

You most likely have a vacuum leak somewhere, vacuum line, brake booster, intake manifold gasket, fuel injector O-ring.

If you put the car in diagnostic mode (jump terminals A and B of the ALDL), this should move the IAC to the fully closed position (you should hear it buzzing).

If not then the IAC may be bad.

But the IAC is designed to control the idle within a range of about 700 rpm, so I still think you have a vacuum leak somewhere.

You most likely have a vacuum leak somewhere, vacuum line, brake booster, intake manifold gasket, fuel injector O-ring.

Thanks for the reply. I jumped the data connector and the new and old IACs both work. Then I replaced the PCV valve for $2.50 for the heck of it. I also started to disconnect fuel injectors to see what would happen and I could disconnect all three on either side of the engine with hardly any rpm difference, then when I disconnected a 4th cylinder it would get rough. I'm wondering if the fuel pressure regulator is inop. causing it to dump fuel all the time and possibly not returning much to the tank. Who knows, I'm going to dig out my vacuum simulator/gage and look up the troubleshooting for the fuel regulators. I have to look for my fuel pressure guage as well. Might just go to the junkyard and see about a used regulator to try out.

Dave