Hey guys! Looking for some help on what to do, or for someone to help me lead me in the direction. My 2004 f250 6.0l has been making some for awhile in the engine area, I thought it was the belt because of the sound it was making, but that wasn't the problem, today when I was driving home it was making a noise on the driver side like there was loose bolt clanking around when I accelerated an than a sound like a back fire out of the tail pipe, than I didn't have much acceleration power after. This only happens when it makes this grinding/ cranking noise. This noise doesn't happen all the time either. I have only replaced the air box, belt, an top idler pulling in the last 5000kms. The truck it self has 275000 Kms on it. If someone can help me out here that would be great!!

 

Take the belt off and spin every pulley . . You probably have a loose one which will help you find problem. It's usually water pump or idler pulley. Yes you can have a faulty idler. Is your alternator working ? Dual batteries will run quite a while and you won't notice till you can't crank to start.