I've spent many a long hour over the last few months scouring Usenet,
the Web, and my Haynes (painful, yes) manual, trying to figure out how
to fix the miss I have in my V6 3.4L 1995 Camaro, now I come to you
for some help.
Let me first tell you what I've tried already:
Replaced spark plugs and wires
Replaced 02 sensors
Installed new intake gasket and resealed manifold
Cleaned throttle body
Here's the problem:
The car starts up, but when it's idling at 900 RPM's, it'll violently
shake/shudder and immediately drop (like a burp) like -50 to -75 RPMS
from where it was idling, seemingly "catch" itself and recorrect
itself back to 900 RPM's. There is a short delay between each
hiccuup; but, it seems pretty consistent when in idle. From low RPM
accelaration it feels sluggish.
I have had the car into a dealer, for the plugs and 02 senors, they
didn't uncover any engine codes when they had it hooked up. I'm
pretty sure the ECM is working, since after I put together my manifold
I forget to hookup the MAF sensor and the check engine light went on.
If I unplug any device, IAC comes to mind for this test, the check
engine light will come on.
I was there when they hooked up a scan tool and it seemed like all the
sensors were putting out "good" results. I haven't run a compression
test on the engine, should that be my first move now?
Based on my most recent research, it seems like maybe my EGR is stuck
open; however, in the 3.4L GM cars these are digital. Is it possible
my EGR is broken and not sending an error code? Also, is it
worthwhile for me to pull it off, look for the valve, and then,
assuming it is dirty, try to "de-carbon" the valve and associated
Otherwise, what else should I be looking at in my car? I don't have a
lot of experience hunting vacuum leaks in hoses, should I be looking
for that first of all? Is the problem I have a "miss" or is just an
idling problem? Got any helpful hints or candid advice? Please post
or email me back at (nospam) email@example.com.