if im goin about 85, 90 miles an hour and hit the gas to go a lil more it sounds literally like popcorn coming from the engine, i origanally thought it was a bad cat that had some crap in it because on initial startup you can hear a little clatter, anyone have a similar problem or know if it is justmy cat thats makin the noise....

also anyone else with a 5.9, what is your average oil consumption?

 

is it coming from the engine or exhuast?

and i use about 1 qt every 3k miles, but im on it ALL THE TIME. Takes about 5.5qt to fill it up, also use 10w30 and mobil one syn, or amsoil syn,

 

it could be spark knock or a miss fire causing that. I get spark knock high in the rpm's the odd time. and I burn about 1/2 a litre every oil change with 10w30 castrol GTX syntec.

 

Sounds like detonation to me. What spark plugs are in the engine? The correct plug for your truck will be listed on the underhood sticker. It will be a Champion part number.

 

Are you driving a quad cab? They have a 97mph speed limiter, are you bumping up against it? It always sounds horrendous, especially the first time you bump up against it.

It's also possible that you have the infamous belly pan gasket leak, especially if you're consuming oil. With the engine off, remove your air intake, and flip open the throttle body blades - if you see oil coating the inside of the intake manifold you probably blew the gasket. At that point you'll have to decide whether you want to replace the gasket, or go ahead and buy/install a M1-2bbl intake manifold.

 

ya not all quad cabs have them at 97 mph i drive a 04 quad cab and mine is at about 115 or 116 mph

 

thats just stupid...but good to know next time ya get in a chase or somthin!