1996 c1500 issues

[TS6235]

These issues started after I replaced the ignition switch harness. High idle on start up, 1800 rpm or so then goes down to normal after 20 seconds or so. While driving on freeway, when I lift off the accelerator the rpm raises a couple hundred rpm's and seems to hang at the slightly raised idle until the truck is fully stopped. After warmed up, turn the truck off and restart it, it will start with raised idle for 20 seconds or so then down to normal, put the truck in gear and the idle raises without touching the accelerator pedal enough to keep the truck going 5 mph or more until you come to a complete stop again then the truck idles down again. No codes are being set. It runs and idles good except this this issue. I did unhook the ground from the battery a couple of times. Ideas?

[speedygonzales]

Does it stay high after stopping at a light then go down to normal? If so, replace the IAC.

[TS6235]

Originally Posted by speedygonzales

Does it stay high after stopping at a light then go down to normal? If so, replace the IAC.

It does, I will try and clean it first and see if it changes anything. Thanks for the info.

If I need to replace it do I need to go with an AC Delco part or are the typical parts store one ok?

[Bayou_Stepsiding]

Hello, i just rebuilt my 5.7 and same problem its called a pcv its on your throttle body. its on the right side of throttle body. its held in with 2 torq bit screws. cost like $35 to fix but will solve your problem. after a while the spring inside the pcv stops getting springy lol. let me know how it goes!

[speedygonzales]

Originally Posted by TS6235

It does, I will try and clean it first and see if it changes anything. Thanks for the info.

If I need to replace it do I need to go with an AC Delco part or are the typical parts store one ok?

Vortec does NOT have the PCV on the TB.

I never saw cleaning fix the Vortec IAC's before.

My normal answer for electrical parts would be OEM. However in this case, the part is so simple to get to, any make would be ok. If the aftermarket does not save you much, then OEM all the way.