I had a 1993 850 GLT which I had been driving for almost a year and it had not been well taken care of and within the year the main seal began to leak and radiator and some tranny. I merely just keep adding fluid until I could figure out what I wanted to do so one day while driving the timing belt broke and yeah well 2400 dollars later I have a junkyard engine new radiator and cleaned up tranny.

Now my problem is the mechanic and i are troubleshooting some of the issues on the new engine because the computer does not want to give me codes (the blinky lights) so essentially the problem is this. When at a dead stop(transmission in drive) and the holding the brake the engine feels like its pulsating the rpms will go between 500 and 1000, but will hold at 850 for a while. The check engine light came on within 5 minutes once the new engine was cranked up and we are trying to decipher what is going on, I have not check the spark plugs, but it's one of my first guesses, however I wanted to see what you guys think, the engine that was transported had 89k miles on it. Thanks for your help!!