I have a 2002 Cadillac Escalade. I have always used premium gas, but want to know if I can switch to regular gas without hurting my engine.

Lower the octane rating on the fuel the quicker the fuel will burn. It won't hurt it, but it may decrease performance a bit..

try mid grade for awhile before you drop to regular. Most GM engines will run on regular (no E85). Depending on your driving style - maybe you will notice a slight drop in performance. As for mileage - "maybe" it will drop a little - but not even close to as much money as you will save going from Premium to Regular gas. If possible, stick with Tier 1 gasoline. It has higher cleaning and performance additives than the minimum required by law.

I saw a TV show (in Canada) where they debunked the myth about regular vs high test - they ran tests and diagnostics and concluded that regular was just fine in all cars. We pay the lovely price of $1.25/litre for regular and $1.45/litre for 93 octane, so I switched to regular - BIG MISTAKE, car started to run crappy and mileage dropped. I went back to 93 octane and after a few tanks the performance was back. ($4.60 and $5.30 per U>S? gallon) I gladly pay the extra!! STICK WITH HIGHEST OCTANE YOU CAN GET

If you went straight from Premium to Regular - I would expect those results. My original post suggested using Mid-Grade which is 89 Octane. Switch to Mid-Grade and stay there awhile. At 89 Octane, it is normally a good choice between the pump 93 Octane and the recommended 91 Octane of some engines.

I always fill up at half a tank so the change down is indeed gradual because it mixes half tank of high test to half tank of low test and you get first time a mixed blend in the tank of about 91.5,second time you end up at about 90 etc.. I'm staying at 93 now that I'm back;only adds $15.. to a full tank (ie:costs me $7. extra each time I gas up and where I live that won't buy me one pack of smokes.)