Throttle Sticking? [Archive] - Forum


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05-28-2008, 09:00 AM
Hey Guys got a weird problem. I was driving my 3400 GT Monday on the freeway and noticed when I pulled off the freeway and stopped the car it was pulling ahead real hard. I kicked the trans into neutral and the engine was reving at about 3000.

After looking around the throttle linkage looks fine, its not hanging, but the engine keeps up the high RPMs. I believe it may be a computer problem because I killed it in neutral at a stoplight yesterday and started it back up, and it went back to idling normal at about 800. No lights come on or anything. You guys have any ideas on what could be causing this? Bad sensor or something?

05-28-2008, 09:38 AM
Sticky TB maybe? If it is Ive still got my stock one. 4 sale.

05-28-2008, 09:49 AM
No its not sticking, I was messing with the Throttle Body and reving the engine from it, to see if the RPMs would stay up because it was sticking. Thats why I am confused, cause the TB is moving freely.

05-28-2008, 01:34 PM
i had this problem a while back. it started in early december when i first got my aftermarket TB, so i thought that was the problem. it would only do this occasionally. then in early april, i was out for a drive and it started acting up really bad, and next thing i know my gas pedal was sitting on the floor. the throttle cable broke. i bought a new one and had it installed in about 20 mins. i looked at the old one and where it was inside the tube thing, it was all frayed and rugged looking. so i would take this into consideration. it doesnt cost that much to buy a new one, and doesnt take long to install.

05-28-2008, 01:58 PM
I could be wrong... I know enough about cars to break them.
I started the car, watched the RPMs, it started about 900 or so, then slowly creeped up to about 2500 in about thrity seconds, so I popped the hood, and tried moving the throttle body to see if it was stuck a little bit open, it seemed to be all the way down.
I manually moved the throttle to rev the engine, but the idle was still really high. I guess it could be the throttle, but restarting the engine, and that fixing it makes me worry that it is a computer issue.

05-28-2008, 02:10 PM
maybe its your throttle positioning sensor then? could be dirty or worn out... i highly doubt it could be a PCM issue, unless you do tuning to it or have replaced it from another car.

05-28-2008, 09:27 PM
There's a recall on some N-bodies involving a stuck throttle and the accelerator pedal. Call the dealership and give them the last 8 digits of your VIN. They'll see if the recall applies.

05-28-2008, 09:58 PM
The throttle might not be closing completly. This would cause the rpms to continue to climb. You may also have an air leak around the throttle, it will cause the same thing. The gasket around the throttle might need to be replaced.

05-28-2008, 10:31 PM
Thanks guys, I will look into all these options and let you know how it goes. Do you think its worth a shot running the computer for Codes?

05-29-2008, 07:22 PM
not really. these are all mechanical suggestions besides the throttle positioning sensor, and if it was that, then it would probably show the ses light.

05-31-2008, 06:50 PM
throttle position sensor

ses light, most of the time, not always

or sticking linkage

06-28-2008, 06:11 PM
I am currently having this problem. I am not sure what the issue could be. I don't think its a PCM issue because since the issue started, I have had my PCM tuned and replaced. So I am not longer using the same PCM. I had this problem for about 2 months, then tore car apart to do a rebuild, and finally after about a month of having it on the road, the issue is back. The TPS has been replaced twice, so I know thats not the issue. The TB was replaced with a 65mm TCE.

Could it be a MAF sensor?

MAP sensor?

Anyone have any other ideas?

06-29-2008, 03:52 PM
I'm still having the problem about two weeks later. It is not as bad now, the engine runs about 1500 for about the first minute of the drive then it is fine. I have a feeling its the throttle body gasket leaking on mine. I want to tear it down and take a look, I just need some time to do it.

07-02-2008, 05:19 PM
normally its one of 3 sensors, MAF, TPS or IAC...usually IAC tho, dirty, stuck open, bad connection. the easiest way to find out is to use a scan tool and look at the values, or just go about unplugging them to see, most of the time its a bad IAC tho

07-21-2008, 03:10 PM
Well, I am still having this problem after replacing the TPS last year, and just replaced the IAC. Do I have to reset the computer or anything for the new IAC to work? What else could it be? It’s not a TB gasket or anything like that, because I just replaced it, and it did it before and after my build.

What vacuum lines would affect the idle?

I didn’t have this problem come back until I took my car to the track after my rebuild. This was about a month or 300 miles after I finished the build.

07-21-2008, 03:50 PM
I've had this problem, it was the throttle cable like jurgs mentioned.
I had the problem with the throttle stuck wide open several times, and could never figure it out. Eventually when i was rolling up my driveway i heard a big clunk and the car jumped forward. I thought my trans blew out then i noticed my gas pedal went limp. Sure enough i pulled the cable and it came out (snapped somewhere in the middle)

Also make sure the thottle isnt catching on the rubber boot that goes on the TB. Had that problem to

07-22-2008, 06:25 AM
I'm still having the problem about two weeks later. It is not as bad now, the engine runs about 1500 for about the first minute of the drive then it is fine. I have a feeling its the throttle body gasket leaking on mine. I want to tear it down and take a look, I just need some time to do it.

This is exactly what happens to me man, I thought it was bad gas I put in but I gave the car quality treatments directly after I knew I goofed. Same exact symptoms, mine revs at about 1.3-1.5 and after I drive about 1-2km shes back down to 700 like normal. I really want to figure this out, I have a GASE too, so its not just a GT problem.

07-22-2008, 10:50 AM
Mine makes a whooshing sound when I first start driving, that is what makes me think it is the gasket. I'm going to change it out this weekend and I will let you know if that solves it.