Had my 2001 2500hd at the dealer last week. Asked about injector test and warranty. Was told that the test was about 2 hours labour. I then asked if this would be coverd by warranty if any of the injectors were found to be bad. I was told that GM would only warranty my injectors if all eight proved to be bad, If they were not all bad the problem would be due to poor fuel. Then went on to tell me about the notouriosly bad fuel we have here in western Canada. (news to me.) Is the dealer correct? I belive I may have some injector problems, butt all eight?