Here's my issue. I've been battling a shuddering/backfire/hesitation problem for almost half a year now. Fast forward to now. I acquired another car that I bought for parts originally, but decided to restore it since it was in much better shape than my old car. I had to borrow quite a few parts as well as the fuse panel/headlight harness to get the car back on the road. It seems whatever sickness my other car had this one has it now. For a while I've been blaming the dizzy for these problems, but I've been through no less than 5 or 6 of them in the past year. I'm thinking they are the cause because a couple times when I replaced the dizzy the problem was solved for a while. Well, this car has the problem with the dizzy that was in it as well as mine so since the symptom did not change upon switching it out, I'm going to rule it out as a culprit. Since my MAF was used from the other car, I went ahead and reinstalled the MAF that came with the new car, but the symptoms were unchanged. The only thing left would be the 02 sensors in the same H pipe that I carried over to the new car. Could 02 sensors really cause that much of a problem with drivability? I'm about at wits end with this! The guy who had the car before me said it ran fine and had none of the symptoms I've described so it has to be something I used from my car. All the rest of the sensors on the engine are the same ones that came with it. Sorry this is so long but I would really like to have a nice running car again!!