I have a 97 RS with all bolt on's possible for my motor. It has just started missing at idle, which I just checked all vac lines that I could see, and I checked the basics like plug wires etc. This was bad, and I'm talking bouncing between 500-1000K RPM's. Couldn't find a problem. After this, I started her up again just for shits and giggles, and it idled just like it used to. Could it have just been a little dirt that went through the injector? That's the only other thing I can think of, anyone have any thoughts on this?

id say 90% of the time a misfire is electrical/ignition related..not fuel. how did you "check" your wires? did you use a multimeter? pull off your boots and look at the coil pack pins. are they corroded? i had a misfire caused by oxidation on my #2 pin. also, your o2 sensor could be going out. thats what mine did when it shit the bed. it got to where it would miss even at idle..and worse as you went up the RPM scale.

No I didn't have a multimeter handy. Tomorrow at work, I will use one of mine. I basically just checked to see if one came loose possibly. Just the basics. As I go up the RPM scale there is no miss whatsoever. Not even when I let off her. Just when I get to idling speed. I will check the o2, and possibly replace it.

i have this same problem, let me know if you can figure out what it is. when i posted a lot of people said map sensor, but who knows

I have narrowed the problem down somewhat, but it has left me almost clueless. This morning we had a terrible frost, so I had to run the defrost. This didn't mean much, but when I shut off the defroster, I would have to keep the RPM's up or it would have died. I immediately thought vac line. It was that bad. But I checked all vac lines I could see, and they were fine. After that, I went out and gave her some hard pulls, and it was perfect as soon as I stepped on the gas. No shaking no missing at all. And now when it idles, it idles perfectly at 900-1K.

So my question is, and seems utterly retarded, does this problem have something to do with the A/C compressor? It has only had this bad idle after using the A/C compressor for the defroster.