2000 426F with sudden change in midrange

[divebobber]

My 426 was running perfectly two weeks ago, then just started running like it had water in the gas...stumbling, coughing etc. especially at mid throttle. Drained and refreshed the gas, no change. Dismantled the carb and went through it completely. All jets, including air jets are clear. Float level good. AP good. Air filter good. New spark plug changed nothing though it almost seems like a spark problem. The problem is not a bog but a terrible stumbling at mid throttle. If I open it up, it will clear somewhat, but as soon as I drop down into mid to almost full throttle range it stumbles again. Closed to mid is ok. Quite a bit of popping on decel too. I rolled the needle on a flat surface and noticed that it is very slightly bent. I.E. as it rolls the tip just moves up and down maybe a half millimeter.

I'm about ready to drop it off at a shop. Any ideas? Can it be something in the ignition module or coil?

[grayracer513]

Try unplugging the TPS. It may not run perfectly that way, but if the TPS or the CDI (or the wiring) is at fault, doing this may clear up your symptoms and help you diagnose it.

[divebobber]

I'll try that tomorrow. Thanks.