1996 Regal 3.8L Misfire Above 4000RPM
I have recently acquired a 1996 Regal Custom, 3.8L Series II with only 38K miles. Car is in great shape but has an unusual quirk - When I rev the engine in park it runs smooth until 4000 rpm - it then misfires, engine shakes, etc. Under 4000 rpm, smooth as glass. This would lead me to assume a coil, wire or spark plug issue. However, if I'm driving and punch the gas it runs smoothly all the way up to the redline (5500 rpm I think) and then shifts properly into the next gear. I would assume if I had a weak coil, plug or wire I would have more problems with the engine under load than revving the engine in my driveway.
I appreciate your thoughts on this......