Mercedes: 1991 mercedes 190e 2.6 trasmission problem, vacuum leaks, fuse box

Question
I was having problems starting my car so I replaced the fuse in the OVR relay behind the battery then the car started fine. About a day later I could feel the car wanted to go by itself when I was stopped at a light or if I put it in reverse the car would reverse with a lot of power kind of pulsating stopping then going without me touching the gas. I was driving down the road at about 40mph when all of a sudden the rpms jumped up and the car wouldn't shift out of first. The car will shift fine into park and neutral but not into 3rd or 2nd which is first low. I was wondering if you could help me get started on diagnosing the problem please.  

Answer
Joseph,
Gremlins of the type are particularly difficult to diagnose. The fact that the OVR fuse was blown, may have something to do with the erratic behavior of your car. There are so many interrelated relays, and circuits that can effect the computer which control fuel deliver and transmission shifting.
Maker sure that you have on vacuum leaks as leaks cause bad sensor reading which in turn cause the computer to act erratically,

I suggest doing a cold boot of the vehicle computer. Release the hood latch, then turn off all accessories and the radio. Manually lock the doors and trunk. Raise the hood and disconnect the battery (-) terminal then (+). Clean  the post and terminals thoroughly. Leave the terminal off for at least 30 minutes. This would be a good time to check the fuses and their sockets in the fuse box. I would remove the fuses and polish the tips on each one and their sockets. Make sure to reinstall them back in their correct positions according to amperage. I would also pull the relays and wiggle then back into their sockets. This will improve their connection.

After  you have completed these projects, reconnect the battery terminals (+) first. Then reinstall the(-) terminal with a quick but solid motion.

Open the driver door and enter the car and start the engine. Watch the Tach to see if the RPM are steady. If the speed is pulsing then you may have a problem with the MAP sensor. Make sure that your intake filters in new condition.

If all else fails, I would locate an independent Mercedes mechanic and have him/her read the codes to see what come up.

Good Luck
Rob