Cadillac Eldorado Backfires

Hi,



I got a 97 Eldorado that has some backfiring and idle issues. I took it to a few different mechanics, but no one could tell me what’s wrong with the car.



The problem typically occurs if I’m slowly accelerating up a hill. Once it hits 1100 RPM it starts to stumble. If I step on the gas it then backfires and jumps up to about 2000 RPM. If I keep the gas constant it will stumble until it suddenly jumps up to 2000 RPM.



The car also runs a little rough when idling every now and then.



Plugs and air filter are new, and none of the mechanics could find anything obvious wrong with it. Check engine light is not on.



Any ideas anyone?