Engine Performance problem
1998 Chevy Cavalier 4 cyl Two Wheel Drive Automatic 100000 miles
I'm hoping someone can help with this, it's driving me crazy. My wife's car has had intermittent issues since a few years ago, we drove it down to FL from Ohio. The car was missing and blowing white smoke, we took it to a mechanic spent $300 to replace plugs/boots/coil pack. Still had a problem. So I took it to a dealership, they said the battery was low so they replaced it along with another part(factory recall) and the car magically ran fine. It has ran fine for the last few years with an occasional cough, until recently. It was running terribly, I rented an OBD which read only one code p0300(multiple ore random cylinder misfire. So I pulled the plugs lets call the farthest drivers side plug #1 and so on down the line. Plugs 2 and 4 looked different bought new plugs and ran it for a bit, pulled them again and again #2 and #4 came out clean and wet. I checked everything out, "borrowed" a coil and an ignition control module from the parts store. No change, I inspected the boots that act as wires and they are in excellent shape. I've had the parts store check the map sensor, cam shaft position sensor, crank sensor, ignition control module, and coils, all tested fine. I've unplugged the o2 sensor and the maf sensor, zero change. I kept hearing a ticking sound, so I thought electrical, on a hunch I went to the parts store and bought a new coil pack thinking somehow the wires inside the pack were shorting out, plugged it in. Ran fine. For about two weeks. Now the missing isn't nearly as bad, and it is now only plug#1 that is wet and clean. Since it is just one plug AND a completely different plug then it has been, I was thinking maybe the new coil pack is grounding somehow to the engine block, but it's black and I don't see ANY signs of carbon tracing. Tonight i'm renting the OBD again to see what it says. I've also done compression tests, all cylinders read the same. This is something to add, the day I got the new coil pack I had the camshaft and crank sensors out, but put them right back in before I put the new coil pack, could it have been the cam sensor? I notice when I unplug it( when the car is running badly) there is no difference in the way the engine runs, which is troubling. I apologize for this being long winded and possibly random, but I'm trying to remember every detail. Thanks in advance, Chad
have the same problem?
Tuesday, August 26th, 2008 AT 3:08 PM