Alright folks I've had the most annoying surging idle issue I've ever encountered. I was made aware of it when I first bought the truck, so I followed normal procedure and replaced all of the sensors to begin with (MAP, TPS, etc.). The idle continued to surge. Ok, I guess we'll move on to fuel issues. There was some stupid gas saving device in the fuel line. Cut that **** out of there, and put all new fuel hose and a new fuel filter in. The idle still surged . Alrighty, I guess it's time to replace all the vacuum hoses. Same ole' ****, still surging. Next I pulled the throttle body off, and cleaned it all up and got it a new gasket (this was today). And after putting it all back together, upon startup it was running smooth, but after a test drive and putting it in park the idle started to do it's thing again. FUUUUUUUUUUUUUUUUU

Any thoughts or suggestions would be greatly appreciated.

 

Bypass your egr completly and if u have cats check them too and theres a missfire sensor behind the balancer pully that sometimes wont show in a check light so un pkug it and see if it helps

 

What year truck? Did you pull neg battery cable off to reset the computer?

 

Nope 95

 

It's an 89, and I just put in a new turn signal switch the other day so yes the negative battery cable was disconnected then.

 

So did u ever firgure out your issue

 

Have you cleaned or changed the idle air controll valve?

 

I put a brand new IACV on about a month and a half ago.

 

Have you sprayed for vacum leaks around intake and upper plenum?

 

Yup Yup Yup, checked for vacuum leaks last week, and put a new gasket on the throttle body.