I had to change the alternator for the third time in the last year just last week. Tested the batteries, fine. Cleaned all the connections. Recharged the batteries before running the truck. Everything metered fine at startup. All was ok til this week. Truck seemed to start hard, lack of turning power. Guage shows below 14 when driving but right after startup it shows above 14. Gradually goes down as continue driving. This all seemed to start last year after the exhaust pipe off the motor cracked (driver's side). I couldn't get it fixed right away and the heat from the motor popped some fuses in the main fuse box under the hood. (ECM fuse ???) . Could this have anyting to do with the problems? Maybe the trailer wiring plug? Any suggestions on where to start would be appreciated. I feel that the way things are now that I'll be replacing the alternator again shortly.