my 91 has developed a habit of having a nasty dead spot and/or stumble in the throttle at part throttle during acceleration. If I accelerate very easily it doesn't do it, and if I accelerate at WOT or close to it, all is fine. It's when I'm anywhere inbetween that it's having fits. It doesn't do it all the time, but it's doing it often enough to irratate the hell out of me. A while back I tried blocking the EGR to see if that helped, and it didn't. Just recently I replaced the 02 sensor, which also didn't help. When using my Auto X-ray, I couldn't find anything out of the ordinary, but I was concentrating on 02 voltage and knock sensor data more than anything else, so I may not have noticed a MAP problem if there is one.
I'm going to check the X-ray again, but has anybody else had this sort of problem? Right now by process of elimination, I've got to think that it's MAP related, but so far I've gotten no codes, my gas milage is unaffected, and drivability other than part throttle acceleration is totally normal.
Thanks for any help.