Problem: Fast idle, about 1,200 RPM in drive and 3,000 RPM in Neutral. Intermittently at first, first time was a surprise.
Historically I know that on the pre-1996 Northstars, this is due to the ISC Motor or Idle Speed Control. Our friend and member @Barry94 did a terrific write-up back in 2005 that has always been helpful in understanding and diagnosing the ISC motor. This thread was a walk down memory lane for me. So many members I had gotten to know in this thread, that contribut