timothymcn: I live in Montana. Doubt there are many other running M42's running the state. Let alone anybody that knows how to troubleshoot/maintain them. It clearly is not a mechanical problem. I swapped the brain and it still runs the same. I backprobed all the grounds at the DME connector and they are all good. Swapped the TPS from an E36 throttle body I had laying around (same part number). No improvement. To add insult to injury my 89 325ix pinched a loaf last Monday. Which is a story for another day. I thought...maybe fuel pump. So I pulled the pump from the ix. It was a Walbro I swapped into the IX within the past 3 years. No change. Car starts and runs. I can drive it. Virtually all of the time, it feels like it is running on 3 cylinders. Any mild grade and the sucker can barely pull the hill. Have to drop a gear or two and rev the crap out of it, even then it just wants to lay down. The car can barely get out of its own way. My wife made an interesting comment last nite... "that car really stinks when you pull away"....hmmm.....crapped out convertor? I guess the best way I can describe the way that it runs is that it seems like it has a butt plug shoved up its ass. Never overheats. I don't know...I like challenges but it is 11 degrees out and I do all this crap in the driveway. Not today. I am not going to bail on the M42 just yet...It has got to be something simple. If/when I find it I am sure I am going to have one of those WTF moments. Thanks for the r3v tip. But...been there, done that. I scored the DME from a cat on r3v (Thanks Justin!). If anybody here reads this post and has had experience with a plugged cat, post up. I am ready to ream the thing. It would be a "no harm/no foul. The only cat I ever had fail was on an 88 Mustang GT. The cores fell apart and rattled like a sum bitch. Ford had a big recall on that one. But I have never had a "plugged convertor". Again, thank you.