mikesta04

So, when im idling, the tachometer dips slightly from 600rpm to around 500/400 approx. At this time the car vibrates a lil (But is definitely noticeable), and the lights dim slightly. Sometimes it even feels as if for a split second its gonna stall, but it never has.

--I also installed a 1000watt amp, however this did not make the problem worse at all! which says to me that its not an electrical issue...

--Also, I bought the car used, and there is some duct tape on the boot between the MAF sensor and the intake manifold. Could that be the issue?

The car is also blowing fuses on the lighter/computer fuse, so i cannot test for thrown codes at the moment.

Any ideas would be greatly appreciated. (I'm in college so i cant just go indiscriminately replacing parts, right now )

Injuneer

Do you have an automatic trans (550rpm idle, in gear) or a manual trans (800rpm idle)?

There can't be any leaks in the rubber elbow between the MAF sensor and the throttle body, or you will have problems with the A/F ratio. When air bypasses the MAF sensor, it screws things up. I'd get a new rubber elbow (use an online discount GM parts dealer, not a regular "list price" dealer).

If that doesn't fix it, the problem may be the idle air control (IAC). If its dirty or not working, it can't control the idle. You would have to put a scanner on it, and observe what the PCM does with the IAC "counts" when the RPM drops. If it tries to open the IAC motor (increased counts) but the RPM doesn't respond, it would indicate a problem related to the IAC.

mikesta04

My bad, its an auto trans. And do you by any chance know the specific name for the elbow? I cant find it...

Injuneer

You want the "1LE" version of the intake elbow, without the air silencer tube that hangs down behind the radiator. Much easier to install. Shoebox has a list of part name and numbers:

1993-1994 1LE intake elbow
(no vent hole for opti) 25147210

1995-1997 1LE intake elbow
(for vented opti) 25147187

Bookmark his site - tons of useful LT1 info:

http://shbox.com/1/4th_gen_tech1.html

mikesta04

Thanks! That was an incredibly useful reply. And that site is also great, and has been bookmarked.

Thanks for all your help