I just replaced IAC valve and cleaned the whole TB UNIT and it still has a idling problem as in if i rev it up the rpms will come down real far about 200 and sometimes shut off...... if i unhook the vaccum line to the PCV valve it runs....... what is the problem??

 

Did you have the negative battery cable disconnected while you were replacing and cleaning?

 

No sir

 

I would suggest disconnecting the battery, and also make sure the PCV is connected to manifold and the other valve cover vent tube is connected to the air box intake. Don't know what it would do backwards other than doil in intake, but who know. Strange that disconnecting pcv would make any real difference...unless it is blowing air into intake....

 

Should i disconnect it and try again? also its a new PCV valve and it is sucking air from the valve into the intake and i have a filter connected to the end of the intake side of the crankcase vent.

 

Could PCV be installed backwards? Which side is PCV on for your truck? (I assume pass side - it is on my 99).

 

yup yup and filter on driver side......

 

I removed the pre cat 02 sensor also and saw no improvements..... should i have done this and then disconect battery or what?

 

UPDATE: I removed my negative battery cable for a few hours and then started my truck let it run for 10 minutes and revved it up and it didn't shut off! it seems this has fixed it with maybe replacing the PCV valve and IAC? Was the computer just used to the bad PCV valve and IAC motor because i know 100% they both needed to be replaced and when i replaced it it was still going off having the bad parts?