I have been experiencing a problem with my new Mark. When the engine is warm and idling there is a slight surge in RPM. Maybe 50 to 75 RPM. This is with the AC and lights off (doesn’t seem to make a difference with these things on). When driving the car the same surge occurs. What’s interesting is that the surge happens at different RPM. It doesn’t matter if I’m at 60 in OD using cruise control or at a steady 3500 RPM in second gear. The surge feels worse as the revs increase. Another interesting thing, the problem gets progressively worse the more time passes after disconnecting the negative battery cable for 30 minutes.
I have been searching several sites and have taken several steps to fix this problem. First there are no codes (bought a cheap code reader). I have changed the fuel filter, spark plug wires and spark plugs. I should also mention I had a bad driver’s side O2 sensor that was replaced. I found a few receipts from the last owner. It appears the he replaced the fuel pump about nine months ago.
I would have replaced these parts anyway. I don’t want to keep dropping dough without a good chance of fixing this. The first thing I did to the Mark was the HID conversion. So I need to be smart with the parts cash.
Any help would be appreciated. I’ve read tons of posts about rough idle, coils, plug wires etc… But I couldn’t find a post describing a similar problem.
Thanks,
Keith
I have been searching several sites and have taken several steps to fix this problem. First there are no codes (bought a cheap code reader). I have changed the fuel filter, spark plug wires and spark plugs. I should also mention I had a bad driver’s side O2 sensor that was replaced. I found a few receipts from the last owner. It appears the he replaced the fuel pump about nine months ago.
I would have replaced these parts anyway. I don’t want to keep dropping dough without a good chance of fixing this. The first thing I did to the Mark was the HID conversion. So I need to be smart with the parts cash.
Any help would be appreciated. I’ve read tons of posts about rough idle, coils, plug wires etc… But I couldn’t find a post describing a similar problem.
Thanks,
Keith