I have a 2000 LS which means its OBDII-b. I know the ECM has some ignition retard features that regular OBDI doesnt have...anyway, my car is aging, just hitting 100,000 miles and recently, after spirited blasts (not even redline shifts or anything, just 50 percent throttle, 6k rpm) like at the next stop light or first stop sign, my idle will be stumbling pretty bad, like its on 3 cylinders.

Usually, i just rev it a bit, or just drive away, and by the next light or stop sign, the idle would be normal again (this verifies it as something non-mechanical, like a blown piston/rings/etc), but tonight was the first time it caused the CEL to flash. it flashed like 3 times quickly, but the light turned green and I drove away, and at the next stop, the idle was kind of high, like at 1100 rpm, but then dropped down to 750, like normal.

I understand this is VERY likely an ignition related problem, but i just want to know what you guys know aobut this, if you've heard about it before. i'm just trying to cut down on diagnosis time. I'd rather pinpoint it than search through multiple possibilities. thanks in advance!

 

it could be the air booster valve. My car had this problem for a while and it would do exactly what yours is doing...the only different thing was that when it was cold it would totally stall out. My case might have been worse than yours though. Just a thought. The other thing could be the iac valve, on the back of the intake manifold. this controls the idle, and it went bad on my car as well. hope this helps

 

How about a complete tune up? Plugs, wires, coil, cap, rotor, o2, fuel filter, oil. Thats what I am thinking personally.

 

yeah, the next day i replaced my cap, rotor and fuel filter. considering i kinda overlooked these 3 items since i've owned the car, they needed to be changed anyway. my old rotor was pretty out of shape, but the cap wasnt that bad. my fuel filter looked pretty bad on the inside too.

i havent seen the symptoms since, but its only been a few days. we'll see...