At my wits end with high idle issues.

[Dennis Wilkie]

I had the same problem with my 92 k1500 and it turned out to be the cruise control cable was too tight and wasn't letting the arm go all the way back flush with the idle screw. It caused an erratic idle and it would start surging sometimes when I came to a stop. I ended up replacing the entire emissions system before I finally figured it out. It also didn't hurt to put a return spring on it.

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[Sparkyenfuego13]

I had the same issues on my 1997. Tool quite awhile to find it. But it turned out to be my fuel pressure regulator.

 

[Zooker]

EGR valve bad?

 

[bigdave84_88]

is the clip on the IAC connector broken if so make sure you plug it in right a truck my son bought someone had that plug in wrong and it was idling around 1200 but after checking everything else out i noticed the plug was wrong so i plugged it in the correct way and rest the IAC and now the truck idles around 750 all the time

 

[PlayingWithTBI]

The first poster told me about this too, I didn't even know such a thing existed.

Here's an article about calibrating your TB and setting base idle

http://www.gmcmidwestclassics.org/Web pages/Tuning the TBI.pdf

 

[Darrell]

Wow... Deja vu !! I'm gonna ride along with my ears and eyes wide open..lol

Not to hijack but I too am having the same issues. Though I was also having an issue of it dying whenever I mash the throttle whether it was on the TBI itself or from the pedal. Coolant Temp sensor fixed that but still having idling problems.

At times it'll idle (in park) at 750 then suddenly ramp up to 1200-1500 then idle down to 1000. It's so sporadic it's driving me nuts.

I've switched out every possible switch/sensor, install (soldered) a few new connectors, new vacuum hoses, new EGR,reset IAC and no improvement. Even pulled and re-installed the intake thinking I had a leak there, nope.

Installed a new adjustable fuel pressure regulator..nothing

I even bought the ALDL Scan Cable program (Red Devil River) from research and thought it was a simple plug and play and that I'd get my reading and make adjustments...lol, Well I'm finding that it's not that simple or I'm totally missing something with the installation of the program.

I can see that there's a wealth of knowledge here and I'd even pay one to resolve this. Wish one here was my neighbor...lol Harder to fix via the net vs seeing and hearing in person.

 

[95flatblack]

Here's an article about calibrating your TB and setting base idle

http://www.gmcmidwestclassics.org/Web pages/Tuning the TBI.pdf

I read this procedure. Really . Think I would convert the tbi to a carburetor. Plenty of instructions online.

 

[Schurkey]

I read this procedure. Really . Think I would convert the tbi to a carburetor. Plenty of instructions online.

Naw, just install a Flathead Ford and a manual 3-speed.

 

[DerekTheGreat]

Naw, just install a Flathead Ford and a manual 3-speed.

 

[PlayingWithTBI]

I read this procedure. Really . Think I would convert the tbi to a carburetor. Plenty of instructions online.

Get a horse and buggy.