I have been intermittently having issues with my truck's idle. Previously it never occured before I changed the spark plugs at 62,000mi. After it began I changed the plugs again, and it disappeared. Now it is back again.My truck will idle erratically, jump from 700 to 1000, drop to 300, hunt around, and occasionally die. I moved the wiring harness of the AC condenser and that helped for a day. I have read about cleaning the idle contral valve but I am not sure that is causing this much of a problem. This is driving me insane. My spark plugs are gapped incorectly (.058 vs .039 for SC applications) but I don't know if this is causing the issue either. The CEL never come on, even during the worst times.

I posted about this previously but no one had any suggestions except the plugs. Anyway I really need help with this issue or I swear I am going to sell my truck ... Nothing was changed but the plugs, and it never had this problem before, when I changed the plugs again it disappeared, only to reapper a week later. WTF GRRRR. I know I have to change the plugs, but it is a real PITA to remove all the SC plumbing/ intercooler, etc and I want to make sure that if anything else is causing this I repair it before I change the plugs and it happens again...

Anybody help, please

 

clean the IAC and check for any vacume leaks... eratic idle is from the IAC or TPS or a vacume leak. check those three. gap on ur plugs seems about right. which plugs are you using? NGK irridiums? do u have an aftermarket throttle body? if so check make sure the voltage on the TPS is correct. but IAC failr and vacume leaks occur. so id check for those two items first. sometimes its just as simple as a bad PCV valve

 

Oh yeah, I forgot to add, I think it might be a vacuum leak. I pulled the vacuum line to my boost guage off and it made absolutely no difference in the idle. I haven't been able to locate any loos lines though, any thoughts on hidden lines? I forgot about that, thanks Faster. I don't have a way to check the voltage on the TPS, but it's the factory TPS, just swapped onto the BBK TB.

How do I check the PCV? I didn't know they could go bad...

thanks

 

PCV is located on the passenger side valve cover. its in the middle of the valve cover. most people who add boost install air filters to filter out the blow by oil.

like so:


and u can check the TPS with a voltmeter when its totaly shut it should be about .93-.94v

 

I added an in-line filter like that on my protege when I ported and polished the intake manifold, to keep it cleaner.

I'll have to borrow my friends voltmeter and see what I can find.

 

Ted' 98 has a good instructional on his website on how to check the voltage and whatnot
http://home.comcast.net/~therazy/Por...eBodyPage.html