[Lycritus]

Did you ever find the problem? My 94 started doing similar last week and I've been trying to determine the problem. It happened suddenly, just started vibrating quite a bit when I started it one day. I've recently replaced the plugs so I decided to take a look at them again. They all looked fine but after putting everything back together, one of the cylinders was not firing at all. I found a bad coil and replaced it, hoping it would also fix the original problem. It didn't so last night I did a long driving test to get more symptoms. When the car is cold, the idle goes to around 1500 and the vibration is very noticeable. Once the car warms some, the idle drops and the vibration is less noticeable until the car is put into drive, then it is bad again. I drove the car as normal until it was fully warmed up, now the idle is close to 600 rpm and smooth. If I touch the throttle, to pull the rpm up but not enough to take off, the vibration is there. Now that it is fully warmed up I opened it up a few times. Acceleration seemed just as good as always although I thought I noticed a few jerks on the way up to 80. I cruised at 65 for some time, letting the tranny get warm and the torque converter lock up. Once it did I slowly pressed the accelerator down to speed up, but not going so far that the torque converter would unlock. It bucked badly when I did that, definitely showing the signs of a bad misfire. Back to the house trying similar slow acceleration as well as stomping on it. Even at 45mph with the torque converter locked, I could get it to buck badly when accelerating slowly. Stopped and reseated the igniter connectors but no difference. Once back in the garage, I put it in park and ran the rpms up. The vibration seems noticeable at all rpms and I could discern a noticeable misfire if I hit the throttle quickly. No CEL and no codes. I could not hear any vacuum leaks but I have not removed the intake.

I'm going to do more tinkering today, check the fuel pressure and the MAF. If anyone has any suggestions I would love to hear them.