1992 K-1500 5.7 V8 4X4 High Idle

[drdeath691]

I just recently picked up a used K-1500 and it was in pretty good shape. Over the weekend me and a buddy tore into it and replaced shocks,fuel filter,radiator fluid,oil,oil filter,pcv valve and few other things. I also added a fuel system cleaner and an oil additive. We also pressure washed the engine and added some steam cleaner spay to the engine. The truck runs perfect now except for the fact it idles extremely high. In park it's idleing around 1200-1300 rpms and in drive around 1000-1100 rpms. At one point it ran normal but now it's high idle at all times. This upcoming weekend we were gonna do the tranny fluid,rear end fluid and plugs wires. We were also gonna try to figure out the high idle problem. My question is would the fuel system restore cause high idle and if so should I wait till I run out the tank to worry about it. I also thought about changing out the distributer cap and rotor when i do the wires since I read on one post that I could of gotten water in the Distributer Cap. I checked for leaks on the hoses and wiggled the sensers while it was running but it didn't change much. At one point I got it to idle way down and eventually killed the motor but I was unable to pinpoint or duplicate it.


Any Ideas....

Thanx

[2000CAYukon]

Spray some Throttle Body cleaner around the base of the TB (especially towards the back of the engine). When my 90 K1500 developed a high idle, it was the TBI gasket.

Also make sure you did not forget to reinstall the Engine coolant temp sensor (neat the tstat on the intake).

I would cover the TBI and Dist with plastic the next time you power wash the engine.

//2000CAYukon

[67malibu]

A sucked or blown in small area of the TBI gasket is quite often to blame for high idle. I had this issue for about six months before I figured it out. The gasket is cheap and easy to change.

[Fireplug]

number 1 cause of a high idle is a vacuum leak.
your year is known for bad tbi base gaskets and bad vacuum lines.
It might also set the mil lite as a o2 sensor code but the sensor is just doing its job so dont replace it

[drdeath691]

So fuel system restore wouldn't cause this??
Also it has a TBI spacer would I need to change a gasket on this also?

Current condition of truck: Idle mostly at hi but sometimes it lowers itself to almost kiling the engine.

Also now I have a popping sound coming from the engine almost like it is missing, but it is not noticable till you give it gas?

[Fireplug]

this high idle started after the engine cleaning???
poping sound is a missfire
WATER IN THE DIST CAP would be the first place i would look

[Fireplug]

also look at the injector spray is it a nice cone shaped mist or is it dripping

[drdeath691]

We found the popping noise. I have a hole the size of a BB in my driver side Header.

Took off the intake and the fuel is a nice cone shape stream.. We are gonna stick with the game plan of replaceing the TBI manifold gasket, Distributer Cap, Plug wires and go from there.

I checked the voltage on the IAC valve per the haynes manuel and the voltage read good (55 Ohms across).

Should I still replace this to be on the safe side ?