I HAVE 2000 RAM 2500 4X4 94000 MILES 360 AUTO AND WHILE TOWING MY TRAILER WITH MY TRACTOR ON IT NOTICED A RATTLING FROM THE MOTOR AND BEFORE I GO TO THE STEALERSHIP AND SPEND LOTS OF BUCKS I THOUGHT ID POST MY PROBLEM HERE.... SEEMS WORSE ON HILLS AROUND 2800 + RPMS. ANYONE HAVE IDEAS..
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Sounds like you're describing spark knock/detonation...try running a higher octane fuel 1st...also may want to have a fuel injection cleaning done, or do it yourself with Mopar combustion chamber cleaner.

AND LOSE THE CAPS!!!!!

 

Is it a rattling or a ticking? Try taking it all the way to 4K rpms, and see if it stops anywhere. It could possibly be the plenum pan gasket.... mine was real doggish and ticked from 2800 - 3200 rpms, especially going uphill.

 

more then likley its going to be plenum pan blown

but to rule out another possibility, check the header/exhaust manifold-motor moutn heat sheilds. Mine were flimsy and loos and making a spark nock/rattle sound from the vibration of the engine

 

Look at the TBs. My '99 5.9 rattled so bad it scared me when pulling my 5000 Lb boat, I did the plug wire mod, and use mid grade when pulling....no issues now. Don't pull in OD !

 

the other day while towing it just got worse. seems to get louder. tried running mid grade and it was still happening this has been a ongoing problem for about the last year or so steadily getting worse...

 

ITS MORE OF A TICKING OR KNOCKING. ESPECIALLY WHILE TOWING... ALSO UNDER NORMAL DRIVING WITH 87 OCTANE.. A LITTLE WITH 89 AND UP.. TRIED PLUGS WIRES AND CAP AND ROTOR FUEL INJECTOR CLEANER EVERY 3000 MILES WITH OIL CHANGES.. IVE OWNED THIS SINCE OCT OF O4 80k MILES

 

TSB 18-48-98

This fixed my issue. If it doesn't it is most likly the intake gasket.