Hello! Time for a new thread here, it's been more than a year since the last one.
I picked up my '87 924s last fall, and have poured a fair bit of cash into it to make it a reliable drivable car. One thing that has confounded me a bit is the idle engine speed "bouncing" between ~ 925rpm and 1070 or so rpm, and the resultant whole-car-'shake' (my engine mounts are a bit tired).
This doesn't happen when the engine is cold. New plugs, wires, cap, rotor have not shown any positive effect. I've checked three times for a vacuum leak using the tried and true brake clean spray method- nada. I've p