HIGH IDLE ISSUE AND INTERMITTANT SHIFTING CAUSE IAC, TPS?

1999 Buick Century

Tiny

saturntech9

September, 28, 2012 AT 1:59 AM

What is the exact code number its setting now?

Tiny

dlvaughn1963

September, 28, 2012 AT 3:05 AM

Will relay later. Also disconnecting IAC DOES NOT change idle issue

Tiny

saturntech9

September, 28, 2012 AT 3:19 AM

If you unplug it it cant change the idle keep me posted.

Tiny

dlvaughn1963

September, 28, 2012 AT 4:00 AM

But how long does it take the computer to respond to the idle setting's return to normal?

Tiny

saturntech9

September, 28, 2012 AT 4:41 AM

Shouldnt take that long.

Tiny

dlvaughn1963

September, 28, 2012 AT 10:23 AM

I'm looking for a good diagram for the vacuum lines and don't see one. Besides the one on the hood of the car, is there another one?

Tiny

dlvaughn1963

September, 28, 2012 AT 12:58 PM

More info.
When I check the idle with the car being cold the idle is ok, just rumbling, however when the car temp heats up, it goes high. I can't find a leak in the vacuum system unless the leak is at the vac line that runs from the solenoid to the canister, and the canister is in the back of the car. I did a ohms/resistance check of the IAC valve and it checks good unless the valve is just plain worn out.

Tiny

saturntech9

September, 28, 2012 AT 3:50 PM

See if the canister purge solenoid is stuck open?

Tiny

dlvaughn1963

September, 28, 2012 AT 5:44 PM

One other has me wonder bout the solenoid, fuel gage doing weird stuff and heavy fuel fumes. Can you tell me exactly how many hoses are connected to the solenoid?

Tiny

saturntech9

September, 28, 2012 AT 7:36 PM

There should be the vaccum source from the engine and another hose that goes back to the canister.

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