I'm looking for a good GM dealer that will work on my 03 duramax with 50,000 miles. I've got the famous engine knock going on. It only shows up when it is under a load at low rpm's 1000-1500 or so. I'm not able to consistantly duplicate the problem unless I put on my performance module. From what I read I'm convinced that I have a bad injector. I've taken it in before and said that I've had cold starting issues and also the knock. These shops hardly work on any diesels though. I'm reluctant to take it to the dealer with the module on it. I'm looking for a dealer that won't put the screws to me. I live in Southwest North Dakota. Anyone have any suggestions?

Thanks!
:grd:
Donny