96 Buick Skylark (High Idle Problem)

[paperjack]

Hello everyone,

I am new to this site and am in dire need of assistance.
I own a 96 Buick Skylark with 171,000 miles on. The car has been an excellent runner and has been maintained regularly.
My problem is that the idle runs high most of the time. It started out occassionally and as the weeks passed it has become more regular.
Most of the time when first starting the car it will idle high, sometimes I will shut the car off and restart it and it will go back to normal idle, but as I drive it, it becomes higher again.
I took it into the dealership on 6/5/03 and they replaced the IAC motor and that seemed to take care of it for about 2 weeks and then it has started up again.
So took back to the dealership on 6/18/03 and this time they checked the electrical sytem and said they think it was a bad ground and fixed it. I picked up the car and on my way home it started up again.
They are stumped and I am now $600 poorer with an unresolved problem.
The comments on this last check are:
P0122 TPS low voltage
P0440 EVAP System
P1122 TPS Intermittent Low Voltage
Test TPS Operation - Ok - check wiring between TPS & PCM - no problems found - clean tighten all terminals - road test - starts running fast after approx 5 miles - test wiring and terminals between PCM & IAC - no problems found - Check PCM grounds - found PCM ground at engine block cracked (resistance was ok) Replace ground terminal
Clear codes - Road test approx 12 miles - Idle speed appears ok at this time.
Does anyone have any suggestions? And is it normal to have a dealership charge you for the work if the problem was not resolved?

Thanks a ton!
Kris

[Flatrater]

Most dealers will charge a fee to diagnos a car fixed or not! This service takes some time to fix the fault, my dealership usually charges 1 hour of labor at the least and if it is a complex problem you pay whatever time I have into it.

On the Sklark's I have found many times that the wiring harness going to the TPS sensor is too tight and revving the engine breaks the wires inside the insulation or the terminals work loose, when the car is in park the wires touch again and the problem goes away. Best thing to do is have the dealer mechanic drive the car with you when the problem occurs he can record all the computer data then go back to the shop and review it to see a glitch which should help narrow the problem down.

Another thing that could cause high idle concerns is a vaccum leak after the MAF sensor.

[paperjack]

Thanks Flatrater - I am planning on having them take another look at it this week.
It is just very frustrating, since paying this car off in January I have invested about $2k into it.
I do know that this last time they were checking the wiring harness for breaks and that is when they found the bad ground wire.
As for the problem going away when it is put in park does not happen with my car, it just continues to race and sounds like it is going to blow up. Yikes!
If I turn the car off and turn it back on it will occassionally run normal but usually ends up racing again down the road.
So I will mention that vaccum leak, I believe that has been a problem in the past - the check engine light has been off and on for about 3 years. They told me that an emissions code kept showing up and that if I loosen the gas cap (or was it tighten?) it would go out on its own. So sometimes the light would go out and stay off for months or weeks and then pop on again for months or weeks. But this never caused any problems with how the car ran.

Thanks again for the info
Kris

[muzzleloader113]

I have the same problem with my 95 Skylark. Replaced the sensors and nothing. I wil try what your return comments were. Thanks for the help.

[Puffnstuff]

Replace your tps. I had the same problem with my 96 with the 3.1 and the tps was the problem. It's not that expensive and easy to replace and will wear out.