Alright, i know the plenum has been beat to death on here, but i question if mine is blown yet.

Its the 5.9l 360 with 130,000 miles
Im getting 9mpg but with no spark knock or excessive oil consumtion(just the usual). And no bad cat as i can tell

I took the air assembly off and looked down the tb and saw some oil but nothin too bad..

 

I have pics but cant seem to find out how to put em on here

 

You need to pull throttle body and look at the very back for oil. Preferably with a small mirror to fit down there. You should also have a PCV valve form the dealer to eliminate that as a possibility. How can you tell your cat isn't bad? Pulling the upstream o2 and driving will usually show more power, meaning a clogged cat.

 

The rear o2 sensor isnt throwing any codes for the cat

 

The cat has to be REALLY bad before the rear O2 will set a code.... plugging up won't do it. There is less exhaust flow, so, as far as the PCM is concerned, the cat is working just fine.

 

what is your driving style? lol You got a lift, big tires? Streamers off the mirrors?

Last time for tune up? (rotor, cap, wires, plugs)

 

My driving style is moderate. I dont slam it to the floor (for the most part) but im not grandpa either..
And yea I got a leveling kit with 33s and with the 3.55 gears tho
Last tune up has been 5 months or so..
Still shouldnt be 9mpg.

 

Those things will NOT improve mileage.....and +1 on pulling Tb off and looking. And what does "no excessive oil consumtion -just the usual" and "saw some oil but nothin too bad.. " mean? My oil consumption is 0 between oil changes. How long since you replaced PCV?

My Ram was a POS before I got it and started to rebuild it. The plenum issues has not been "beat to death" on here but is a common design and operational issue. It was only one of the several problems I learned about here and resolved. Another thing I learned - do not discount the knowledge and advice here. Lots of experience that is willingly shared - more so than any other forum that I visit!

 

Now that's something to +1 on...

 

When I looked down it had a light thinning of oil, wasnt fresh looking tho.
Havent replaced pcv in atleast 4000 miles..