I've got a 1997 Mystique 2.0 liter with 164,000 miles and have had very few problems over the years. I have a couple of recent problems I'm trying to solve but the biggest one happened late last week while I was driving home from work and had my car on cruise control (typical for me since I drive a lot of freeway miles). While driving at highway speeds of between 65 - 70 mph, my car suddenly and without warning reved higher than what it was set at. The tach was reading approx. 2700 rpm for this speed under normal conditions and it was surging upwards to something close to 3200 - 3500 then comes back down to where it was. To my knowledge, I have no trouble codes setting the ECM check engine light so I'm at a loss for what the problem could be.
I have checked for the obvious - vacuume leaks, disconnected sensor wiring etc and could find nothing wrong. I thought possibly the transmission might be slipping but this does not happen at lower speeds (under 55 for example). There is no slipping in any of the gears coming out of park or reverse so I don't think that the transmission would be the problem. As I stated, this issue Just Started and without warning !
Over the weekend, I changed plugs and plug wires, because I have had an idle surge and an engine miss (sputter) as well and thought the problem was ignition wiring related. I even pulled the MAF sensor and cleaned that thinking the sensor was gummed up or something. Nothing. I did have an oil leak and changed the timing belt over the weekend and resolved the oil leak part of the problem because the valve cover gasket was bad. Afterwards, I took the car out for a test drive and the problem has not disappeared so I could use some help on this one. Especially the surge that is occuring at highway speed. I've had the car with the cruise control enabled and disabled - it does it either way. Any help soon would be appreciated !
Monday, April 23rd, 2007 AT 12:03 PM