NastyL98_T/A

I need some quick help. My car is shaking really bad at idle. My guess it that it's missing on one or more cylinders. Checked the plugs and they're all fine, new wires and coil. All connections are tight. The shaking is real bad at idle up to 1800-2000 RPM's at which point it smooths out. What else would cause a miss this bad? It's a MAF L98. New cap/rotor too.

gta_88_kicks

me 2, i have all new ingnition parts too, but i found at least one inj. leaking and the others have to be crummy and dirty too, so im sending them to cruzin perf. to get them cleaned, see what happenes after. hopefully it solves it

razor

...is the motor surging badly at idle??? If I had to venture a guess on this without more info I would say EGR valve or seloniod. Try unplugging the vacuum line to the EGR valve and plugging it. Check idle and report back.

Z's r Best

I've only had this happen once (on my S10 Blazer, not my IROC) and it was the EGR valve stuck partially open. I popped the pedal down pretty hard and when I got to the next light it began to miss badly and you could smell the gas. The check engine light came on and I drove it home. I pulled the plugs to look for one or more fouled plugs but they were just wet with gas, not yet oily or fouled with carbon. I revved the engine up again several times and it went away. The stored trouble code was for the EGR valve. If the EGR is even partially open at idle speeds you get too much already burnt mixture into the cylinder and it doesn't burn too well the second time around. That might not be it, but it was on mine.

ULTM8Z

I'm about to replace my valve lifters this weekend for that very problem. Having gone through and verified ignition, fuel, cylinder pressure, and leak-down in each cylinder, I'm left with only the valve lifters as a possible culprit.

Do you have access to a scanner? If you do, check your O2 sensor data- it'll help you decide whether you're dealing with a fuel or ignition problem. Of course if the problem is on the side of the engine without the O2 sensor, you're hosed.

NastyL98_T/A

I've got no EGR on the motor, spot on the manifold for the valve is blocked off . Where should the 02 sensor counts be?