81c3

This time the values were 12.2 accross the board......engine was cold though. I checked the spark & it seems strong. I pulled all the plugs & looked at them. All are still white. Most were pretty loose. #7 in particular was letting oil pass by and get onto the boot. I put a dab of antiseize on all the threads & di-electric grease on all the boots.

Some freaky chit happened though......when I started the car it let out a heavy white creamy smoke!! It ran rough as heck & wanted to die. The SES light was on. I disconnected the battery,hooked it back up & the same. Next I went to the ECM & unplugged all the pin connectors, and plugged them back in......started it up & it was good. The Service Ride Control light was on until I backed up about 10 feet & its been off since. ***one funny thing is that everytime I drive a couple of miles, the LTPWS lite lights......this time after about a 15 mile round trip...no light***

I went for a ride & it seems very responsive & pulls hard. The warmer she gets, the better she runs!!

BUT..........the original problem still persists....what now?

petefias

The injectors checked out OK electrically. They still could be the culprit if the spray pattern is bad and they stick. That is a common problem with pre '93 models. I assume yours is a '91.

You did not mention if the vibration was always there (since you've owned the car) or if it started after you did your maintenance. Does the vibration exist if you stomp on the accellerator (wot) from 900 to 2500?

You could also check the resistance of the ignition wires and coils just from end to end (without removing the plenum).

Checking fuel pressure is also relatively easy.

Beyond that you will need shop equipment and higher expertise (i.e. scanner troubleshooting).