Hi all. I wanted to let everyone know that the miss I had in my Bonne is now history. The problem - busted valve spring on the #1 intake valve. She runs like a bat out of h*ll now. I drove this car for a long time like that, and I am extremely lucky that I didn't suck a valve. Anyway, I am now one happy guy!

Springfield? You gotta be kidding me. I would have given you the spring and changed it for you.

I'm 35 minutes North of you. And I have two that look like yours.

I just found the problem yesterday. One good result (other than the car running like it should now) is that I scored myself a scan tool (AutoXray 5000). That'* how I narrowed the problem down. The scanner told me that the #1 cylinder was weak while the miss was there. I eliminated spark and fuel as the problem, which pretty much left only mechanical. Plus, I learned a whole bunch about how the Bonneville ticks, so that'* a good thing, too.

How does the scanner know anything about individual cylinders on a 92?

I don't know, but it did. I tested it by pulling the #3 injector plug. The scanner indicated the #3 cylinder was weak.

Only because you pulled the plug.

You caused the 'weak' by doing that.

That'* right. I wanted to make sure the scanner was indicating the cylinder that actually was weak, instead of telling me that I had "1" weak cylinder, but not telling me which one it was. By creating a miss in another cylinder (#3), and watching the scanner to see if it called that cylinder weak, I verified that the scanner was telling me the problem was in the correct cylinder.

There are no sensors or capability in your PCM or engine to determine a weak cylinder in any way.

The scantool was either configured wrong, or you were misinterpreting the data. The PCM and sensors can't even detect wich cylinder may or may not have a misfire on your car, nor can it determine if a fuel injector is firing.