I just bought a Blazer a couple of days ago, and I'm experiencing an issue with the idle. Sometimes when you shift from park to drive, or drive to reverse, etc. the engine idle will dip down and then surge a couple of times before it levels out. In park, if you rev up the engine and then let it idle, it will do the surging thing before it stabilizes. I believe that it does this especially when it is cold. Any ideas? Thanks!

 

I wonder what you're driving.

 

Woops. Sorry about that! It's a 1995 2dr, 4X4, A/T with the Vortec engine.

 

*Moved to '2nd Gen Tech'*

The areas I would look into would be the Idle Air Control (IAC), a vacuum leak, and the fuel filter. The 'search' function should give you lots of info on these subjects. Any other questions, get back with us.

 

Definitely sounds like a sticking IAC valve. Remove it and clean it and the bore. Do not try to move the valve itself by hand. Just clean and reinstall. See if that helps.

 

Thanks! I'll check that out. I'm kind of waiting for my Haynes manual to arrive before I get around to breaking anything.

I checked under the hood, and there is this little rectangular device just to the right and a little back from the throttle body. It looks like it is missing a cover and has a gel-like substance filling the middle. Can anyone tell me what that is?

 

If you are having idle problems with a 95 i would do a fuel pressure leak down test, as the injector spider assembly's seem to dry rot and leak fuel into the intake.

 

Thanks. It seems to fluctuate a little at idle and then like I said about hunting for the idle when shifting from park, etc. Could the dropping then surging then leveling out condition be caused by the spider assembly? But actually, I don't really know exactly what that is...

 

can you post a pic of it? jp

 

it could be cause by that but like i said, you must do testing before you start throwing parts at it or you could just be wasting money. and the spider assembly is located under the upper intake and driects fuel to the approiate cylinder and also had the fuel pressure regulator built in, so i guess you could call it a modified fuel rail and fuel injectors. search around the forum, im sure theres a thread about how to replace the spider. heres a pic of it http://www.napaonline.com/Search/Det...+50014+2014003