Misfire? *VID INSIDE* M30b35 swapped E30.

[Mr. Burns]

I think I'm detecting a bit of a misfire at idle, and as I rev the car.

where would I start in efforts to smooth this out?

https://www.youtube.com/watch?v=w71uw1-S7Bw

[Jb325is]

Pull the wires off the plugs one by one with engine running to see which cylinder(s) is affected. Are you running b35 harness with the injector box? Make sure on of the injector plugs didn't back off. If you are able to isolate the misfire to one cylinder, and there's nothing obvious wrong, do a compression test. My m30 blew a headgasket between cylinders, and only indication was a misfire.

[Mr. Burns]

Pull the wires off the plugs one by one with engine running to see which cylinder(s) is affected. Are you running b35 harness with the injector box? Make sure on of the injector plugs didn't back off. If you are able to isolate the misfire to one cylinder, and there's nothing obvious wrong, do a compression test. My m30 blew a headgasket between cylinders, and only indication was a misfire.

I'm not burning any coolant, and the engine runs ncie and cool (rare for a M30 in E30)
I'm running a b25 harness.
i'll pull the plugs as you said and try to isolate the cylinder.
I've been noticing there's a definate "surge" when cruising at times too, where it feels as tho the engine is pulling back slightly, then clears up.

I don't drive the car enough to really get a good feel for it tho.

[lukeADE335i]

I was going to point out that the M30B35 has a pretty lumpy idle, but that's definitely a miss - you can hear it higher in the revs too.

Hopefully just a crook spark plug or lead. Are the distributor cap and rotor fairly new? The ignition system is definitely the place to start.