Mitsubishi Repair: 2001 Montero Sport, vacuum leak, butt splice

Question
We recently replace the air compressor. We had to cut the switch off the old compressor and butt splice the wires together so the plugs would match up. The compressor was the same but the plugs were different. Now, my car will not idle. I can drive it as long as I keep the gas to it. Has something else gone wrong or do you think it is related to the new install of the compressor?  Note: I did drive it without problems to the Doctor's office which is about 10 miles away. When I got back into the car it would no longer idle.  Thanks for your advice.

Answer
GAllen: Good question.. I would try having the car coded to see what the computer kicks out on this. But still when you replaced the compressor are you sure when putting the car back together, you put everything back as it was before. You did not have any parts that you could not remember where they went did you? :~) Ok, when sometimes we do work on a car, putting in a new part, we might bump something loose without meaning to.When is the last time you did a good tune up? Are you sure the compressor was the right part? As it might be to much for your car to pull when you turn on the ac. Ok, here is an idea for your a vacuum leak. Could you knocked off a hose someplace or not put one on that might have something to do with vacuum? As my manual say this vacuum leak, leaking EGR valve, spark plugs needing changed, air filter clogged, fuel pump not delivering enough fuel, leaking head gasket, timing belt and or/pulleys worn, camshaft worn. Some ideas to check but I would go with that vacuum leak, because you could have knocked off a hose someplace when doing that compressor. Hope this gives you some ideas to check and good luck! Linda