Engine Performance problem
1996 Mercury Sable 6 cyl Two Wheel Drive Automatic 75000 miles
My 1996 Sable frequently idles at 900+ RPM in Drive, jumps to 2000 in Neutral. This happens on a cold start, or frequently after 1/2 hour of driving following a warm start. Frequently, turning the engine off and immediately re-starting it will fix the problem temporarily.
I have replaced the Idle Air Bypass valve, and cleaned the Mass Air Sensor. I have had the car back to the dealer's twice, but it always behaves fine at the dealer's. When I get the car back it runs perfectly for about two weeks and then starts to act up again. The mechanic says he has done nothing except to connect the computer and run the car at idle for a while. Apart from charging $98 for not diagnosing the problem, the dealer has done nothing to help me.
Any help would be welcome.
Would it make sense to buy a cheap engine code scanner and leave it connected while I drive?
Monday, October 20th, 2008 AT 12:00 PM