Thanx for the reply David.

I mean that removing any of the back three plug wires makes no change in the apparent miss or jolt that the engine is experiencing. When a wire is removed, the idle will fluctuate (rise) briefly and return to normal. The only difference is that the front wire causes two of these misses or bumps per revolution when removed. As I said before, each jolt also generates a higher pressure exhaust burst from the tailpipe. When starting from a stand still, the car's acceleration is jerky, coinciding with each jolt.

I am reluctant to use the word miss because I am not sure that is what the engine is doing. I expected to get two of these bumps or jolts out of the engine when I removed any one of the three undamaged wires and I did not. The back (rearward) two wires had the same effect on the engine as the second from the front-most wire, which is the "iffy" wire; giving one jolt per revolution. Only the front wire removed produced two jolts.

If it were missing, then any of the three "good" wires (when disconnected) should have also produced the same double jolt situation.

A little additional information. This problem at first only sometimes appeared after being warmed up and running for 15 to 30 minutes, sometimes longer, sometimes after about an hour. About 3-4 days after this began, it started doing this all the time, starting from cold or hot.

Only rarely when testing the wires did I notice that the engine would sometimes skip a jolt and run smoothly for that revolution.

The coolant sensor tested out ok. That is what I thought the problem might be after it apparently turned out not to be the "iffy" wire.

If, when you suggest disabling the idle air control system, you mean shorting the red/white wire on the open connector between the battery and coolant reservoir to ground; I have tried this only to have the engine die. The car has done this even before the current problem when it ran just fine.

I also put a stethoscope to each injector and all were firing. I have not pulled them out to check for clogs yet; I am hoping that someone has had this experience before any can point me in the right direction first.