Engine idles too high?

The relearns you're referring to also include short and long-term fuel trims. The short-term fuel trims, (STFT) is a set of data points that modify fuel metering right now to achieve a perfect mixture. You will rarely notice when those have been erased because they begin to update as soon as you start the engine. When the computer sees it's always making the same corrections for the same set of conditions it moves those numbers to the long-term fuel trims, (LTFT). Those are what it starts running off of each time you start the engine. As an example of the things it looks at, if you do get more air to go into the engine the computer is going to add more fuel. Now it will see a higher than expected idle speed with no corresponding change in throttle position sensor reading. It will be confused if it can't reconcile the higher speed to the closed throttle.

This guide can help us fix it

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

Please run down this guide and report back.

2006 chevy silverado 5.3 will not idle down untill you stop I used the seafoam spray in the intake through the front of the throttle body like it said to I also removed the throttle body cleaned it and changed the plugs, it idles fine and runs fine it is like the throttle is sticking untill you come to a stop then it just drops to the correct idle

Is this a throttle acuated control module? Or does it have a throttle cable? If it is the throttle by wire system, which is failure prone, I would check with your local GM dealer about getting the pcm reflashed with the latest calibrations which they have come out with to address certain throttle related issues.

This is a computer acuated throttle there is no cable.

If it is the throttle by wire system (has throttle acuated control module), which is failure prone, I would check with your local GM dealer about getting the pcm reflashed with the latest calibrations which they have come out with to address certain throttle related issues.

My husband drove his truck to work this morning and when he went to go get lunch, the truck started up fine and he drove over to the gas station. When he started up the truck to leave, the engine wouldn't rev up, it justs idles. He couldn't get it to do anything else. Is this electronic- or is it mechanically connected to the trottle valve, what are your thoughts?

It is an electronic throttle control system. There is most likely a trouble code stored in the system. It is probably operating in reduced power mode.

at start up it idles fine but after driving for 20-30 minutes it starts to idle at about 1000-1500, I can kill it for about 20 seconds start it and it idles fine for just a little while then back to high idle. What could be causing this? I also have aftermarket remote start could this be causing the problem?

is it setting a check engine light? your IAC (idle air control) might be sticking.

No it is not giving a code, is the idle controller repairable or do I have to replace it?

replace it. but if i was you i would go to the local shop and have them scan it. sounds like a sensor could be telling it to raise up. or like i said the IAC could be doing it.

Is the IAC the small wire looking device inside the air intake tube? if so I sprayed some carb cleaner on that abouta month ago, someone told me it would help with my gas mileage!?!?!?

Tip of advice, never never never spray carb cleaner on anything on a newer car unless a trained mechanic tells you to. Sounds like you sprayed the MAF sensor. that may be your problem. You are gonna have to have a scan tool to see what it is reading. And no that wont help with gas mileage.

Thank you for all of your advise, I guess I need to quite taking advise from those self proclaimed mechanics : (

My truck accelerates properly up to about 40mph then it revs up to about 4500rpm but no acceleration. I let off the gas for a spilt second this allows the truck to accelerate again. Is there something wrong with my transmission or any ideas what could possibly be malfunctioning??

Andy

Yes, you could have damaged the MAF sensor. The IAC is located on the side of the throttle body.

Hi there,

Thank you for the donation,

I would be getting the transmission checked out as i feel that there may be a problem with a shift vale, a transmission specialist may pick this up with a road test, start here.

mark (mhpautos)

When I start my truck for the first two to three minutes it runs terrible it will almost die out. then it rev's up by its self. I have tried to figure it out but cannot. please help.

Do you have the electronic throttle or throttle with cable?

It has a cable.

Okay, start by cleaning out the throttle body and idle air control valve. If you still have the same problem then replace the idle air control valve.

Seriously great advice you really nailed it. problem solved. thanks a lot!

as soon you start the car it goes into high idle like your foot is on the gas pedal

Do you have any codes in the computer? Also have you checked for vacuum leaks?

Your welcome?

Sounds like an idle air control valve check and clean it and see what happens

I do not know why the question mark. Was suppose to be a smiley face :) Glad it worked out. Let us know if you need anything else.

I dont know why the question mark. Was suppose to be a smiley face :) Glad it worked out. Let us know if you need anything else.

Hi,
My truck has a very high idle. I get a DTC P0507. This is what I have done so far: REplaced IAC, MAF,TPS, fuel pressure regulator and PCV valve. I cant find any vacuum leaks aorund the intake manifold, throttle body etc... In fact I can take the line off the fuel pressure regulator and it has no effect. If I goose the throttle cable near the TB it revs up to 2500 rpm and slowly comes down to only 1500 rpm. Any ideas would be great!!!

Thanks

Have you checked the fuel pressure as well as the regulator?

I changed the regulator in the first place for another issue, the fuel pressure at the rail bleeds off very fast after the engine is shut off. I had fuel leaking from the regulator when the vacuum line was removed. Replaced regulator, but it still bleeds down...probly bad pump check valve? Anyway I get about 65psi at the rail at idle.

Thanks for the quick reply

It should maintain pressure for some time. Yes, either a leak in the system or a bad check valve in the pump. If it is a leak, it may be causing the engine to run lean which can affect the idle.

The truck will be running just fine and without warning it will not idle down when I take my foot off the accelerator until I come to a complete stop. It will keep doing the same thing until I shut the engine off and restart the truck. I replaced the throttle position sensor without any change. It seems to do it after the truck is warmed up. I have not noticed the problem when the truck is cold. I could keep replacing parts until I go broke according to the troubleshooting book. Help!

Check the throttle plate to see if its sticking.

Check throttle plate for sticking open

I took the throttle body off and cleaned it 2 weeks ago. The plate is not sticking. Do you have another solution? Before you answer, I have also considered replacing the EGR valve, the idle control sensor, and a few other parts. Please tell me you can give me something I haven't thought of.

Any codes? 02 sensors come online at warm up, how many miles on this truck?

156000 miles on the truck. no codes, no check engine light, just a high idle when I least expect it.

what size motor? what trans?with or without a/c?

6 cylinder 4.3, five speed, with a/c