High Idle Issue.......???

98GTcoupe · #1 (**permalink**) 02-15-2008, 12:06 PM

Hey All,

Im a newbie here to this forum. I need a lil help. My GT is idling very high while in park after a long period of driving. It will automatically idle at 1500, an then you hit to gas to see if it will calm down an it will idle at 2000rpm. So, today, My buddie an I will scan it, but i just replaced the Intake air temp sensor an it ran great. So i will re scan but also does anyone have any idea what it may be ???

Thanks,

Newbie

Dyno Brian · #2 (**permalink**) 02-15-2008, 12:25 PM

Either a dirty IAC Motor or Vacuum leak.

98GTcoupe · #3 (**permalink**) 02-15-2008, 06:14 PM

Yeah,
Sure was a dirty, really carboned up. I took out the MAF, TPS, IAC, IAT and cleaned all an went to town on the throttle body with some cleaner. Then put it all back on , rescanned an got no codes.
However,
It still seems to idle a bit rough. I think it maybe the Bosch Plugs. Probably need to get some autolites.

Thanks for the reply

blitzstreik · #4 (**permalink**) 02-15-2008, 09:45 PM

Yea, change your plugs and maybe run some injector cleaner too.

98GTcoupe · #5 (**permalink**) 02-15-2008, 10:16 PM

Im currently runnin Lucas cleaner threw the system with 93 octane... So we will see...

Jr's3800 · #6 (**permalink**) 02-20-2008, 12:01 PM

Scan the PCM again to see what the TPS values are at Idle

98GTcoupe · #7 (**permalink**) 02-20-2008, 05:44 PM

Well, I replaced the IAC, and TPS, so it seems to be running fine, but i took out the IAC, an TPS and cleaned the old ones, and it ran ok, but for cheap insurance i just replaced them. Didnt cost to much anyways. But it still seems to idle a lil rough. I just cant figure it out. I havnt been able to re-scan it yet. Hopefully i will be able to soon. My buddie has the Auto-tap. But the only things that could be wrong with it now that cause the rough idle have to be either an Injector, or the plugs, or wires. But before when i scanned it did a misfire test an everything was ok. So, its not misfireing. Plus the idle isnt that rough. Just a little. seems odd, thats all.
Thanks for the input,,,

Greg

98GTcoupe · #8 (**permalink**) 02-21-2008, 10:06 PM

OK,
Well, heres an update. Hopefully someone has some input on this subject...
Well its been bout 3 days since i ran the car. Shes a garage queen. Doesnt see snow or rain. SO anyways, i start her up an let her run tonite for an hour to to make sure everything is ok, because im takin the jeep out of town an my wife will have the GP this weekend. So anyways, she still has a bit or a bumpy idle. I havnt had a chance to check the plugs or scan it lately. The Air Force keeps me really busy. So does anyone think its my Bosch plantium 4's? I put them in at 87,xxx an she now has 101,xxx on her.I have replaced all but one coil pack, an all plug wires with accel wires.

Any ideas?

Thanks,

Greg

QwikGT · #9 (**permalink**) 02-22-2008, 12:57 AM

i would put in factory ac delco plugs. pick up a new denso O2 sensor and see what happens. i used to run autolite 104's and got real ****ty mileage, i know have factory plugs and have no problems. we're N/A so we dont need cold plugs.