recently acquired and i am mainly having to work on external engine parts and alot of original part replacement, alot of the hard work has been complete but as usual alot of the original parts need updated or replaced. anyhow ...



my idle recently jumped as if my timing is changed. i do not have a tachometer but seems that the truck idles up to about 3500rpm,i have been told it was the TPS. is there a way to check this. i havent even seen if i have one but was told the first thing i would need to do i buy a OBD1 test kit and go from there... any remarks or words of wisdom ?

little preliminary test: pull all of the fuses for the ECM(or disconnect the battery long enough) wait for a few minutes, then plug them back in, and see if it fixes your idle.

Explain what happened when you first noticed the difference. At any point were you under the hood? For example: Did you change the oil and when you started the car again you had the idle problem.

changed the alternator and re-wired the starter power cord and the rest from battery to components. but as i dug into it i saw some vacuum hoses under heavy wear so i replaced the "L" shaped connectors and all is well now ...

is this mainly a Bonne forum. thought it was for all GMC (and associated vehicles) ?

this originally bonnevilleforum.com but we merged into GMForum.com and cover all gm vehicles

The usual culprit of a weird idle condition is a vacuum leak. Please check all of the vacuum lines for any leaks.

Also, did you try the ecm reset Robert mentioned? After a reset the ecm will do an idle relearn.

Here are the typical idle relearn steps:

Step 1

Restore battery power and turn off air conditioning controls.
Step 2

Run the engine up to operating temperature and shut off.
Step 3

Apply the parking brake. Start the vehicle and place it in drive (A/T), or neutral (manual).
Step 4

Run the engine until the cooling fan has cycled on and off, or for a maximum of 10 minutes.
Step 5

Turn the ignition key off for at least 5 seconds.
Step 6

Restart the engine and again shift into drive or neutral. Allow engine to run for at least 5 minutes.
Step 7

Shut off engine for 10 seconds and restart.
Step 8

That should do it. With engine stabilized and in closed loop, the IAC motor values should be between nine to 12 counts. If not, the adjustments may be tailored by adjusting the minimum air rate screw. More throttle valve opening equals lower IAC counts. Less throttle opening equals higher IAC counts.

If this does not work please let us know!

Yes! We are growing to incorporate all GM vehicles. If you have good knowledge of GMC SUVs then please stick around! We could use all the help we can get!

x2

yes please do stick around like said we always need more brainpower for gmc chevrolet and well any other make as well

sorry i didnt update earlier, problem solved.

i removed all lines from carburator and cleaned them (excessive junk and build up) when i replaced the lines the idle dropped to expected RPM.


seems to b just a loose hose.
thanks for your suggestions and help on this matter