1991 Nissan Sentra

Engine Performance problem
1991 Nissan Sentra 4 cyl Front Wheel Drive Automatic 150000 miles

I have the 1991 Sentra. I recently put a new distributer on the car, replaced all plugs and wires as well as a new cap and button. I have great spark coming out of the distributor, and to each plug. I can pull the wire off #1 and there is no difference in the cars perfomance. Pull #2 and the car almost dies. I pulled the plug from each cylinder, and 2, 3, and 4 were perfectly burning plugs. Number 1 was COVERED in oil and gas. The car runs as long as it is floored, but when od kicks in, the car shakes and bucks. I am sure it is from only running on 3 cylinders. I run a compression check, and it was about 140? I am stumped. Anyone have any ideas?
October 2, 2010.

140 sounds sufficient, but what is it compared to the other three out of curiousity? Does it run well after replacing the fouled plug, and how long does it take for it to foul? Is there any blue smoke indicating that it is burning oil, abnormal oil consumption? Do you know the history of the vehicle, has it had any repairs that may be relevant. If you have spark, and compression, have you verified there is fuel injector pulse. You can listen to the other injectors with a mechanics stethoscope, or a long screwdriver or rod that will transfer sound. Listen for a difference in the other three, as compared to one. If it is oil fouled, it should run for a spell with a new or cleaned plug. See how long it takes for it to foul. I would suspect then that you may have guide seals, worn guides, or something from the top. An oil ring problem would most likely be a consumption issue, with or without some blue smoke. If you had a valve opening problem, you may see an indication when comparing compression test among the other cylinders. An intake valve issue, say not opening for some reason, would make it slow to build compression, and in theory, may pull oil past the rings. An exhaust valve concern would possibly build compression faster, and possibly higher than the others. If after putting a clean, or new plug in the cylinder, and it misfires from the start, I would suggest a possible valve problem.

Oct 3, 2010.