M20 engine miss

[3dtoddd]

My e30's M20 isn't running at peak - well, it runs great, but it has a drop in rpm as it idles and even at static higher rpm. Example, rev to 2500 and hold, the motor runs smoothly for a few seconds then drops about 100 - 150 rpm and stumbles a little then regains to smooth and steady 2500. It does the same at idle. I've checked the plugs, wires, filters (fuel & air) but am at a loss. Got any idears? Thanks!

-3D-

[Wayne 962]

Can you provide more info? When exactly does it do this? After running, while driving, when it's hot? Cold?

-Wayne

[3dtoddd]

Hi, Wayne. It does it most all the time, hot or cold, driving or sitting. When it is smooth, it is very smooth. The rpm drop and sputter is every 5 seconds or so. It has new injectors, new fuel filter, air filter - wires are fine . . . it was suggested that I consider the reference sensor/speed sensor. I cleaned the idle control valve too and it is operational. Thanks for your help.

[nictor]

Try using BOSCH SUPER 4 PLUGS and see how it behaves.

[3dtoddd]

Thanks, nictor - I'll give it a shot. I did notice the other day too that while working on it in the garage and while it was running, it smelled a bit rich from time to time - I wonder if it has something to do with a sensor that makes the brain think that it is still in warm up mode. I appreciate your ideas -

Toddd