92 Explorer Deisels

My 92 4x4 explorer diesels when I return from a drve and turrn off ignition if i let the car sit for a bout a miute or so and the idle will drop from 1000 to about 500 then I can turn off and wont deisel ,It also does it most when I run the A/C ....
Thanks for some info...

sounds like you have a vacume leak, or possibly the charging system, it could be the alternator, with the a/c compressor running it takes away almost 40 percent of your power, low charging system could cause the motor to run bad, I reccomend you get a meter and put it on the battery and see what its charging at it should be charging about 14 volts. let me know what happens.......GOOD LUCK