allenmehrer

I've recently taken off my throttle body to inspect my intake manifold and i've realized that its lined with oil and a little bit of dirt, though it could just be dirty oil. what is this cause from? should i take my manifold off and clean it? I'm just trying to figure out why i've lost 4 mpg lately on my 4.8l 03 RCSB. i use to be able to get 20 mpg freeway, but no luck anymore! any help would be great.

oh and i've tried that sea foam stuff and it doesn't fill the intake so i don't know how its suppose to clean the sides.

ssdan

You should clean your intake, it should always be clean but it also should'nt get dirty. Check your injectors too and I’m guessing your filter is clean so in that case I don’t know of anything that would screw with your mpg that much. sorry if i didnt help

quicksilverado

iTrader: (8)

If you put a catch can on the truck it will prevent alot of the oil buildup in the intake.

Bowtie70SS

iTrader: (10)

They get dirty because only air flows through them, and not fuel. As stated above the catch can will help prevent blow by oil from caking it up. The PCV valve allows a small amount of oil vapors to be sucked in and it cakes up in the intake. Later

Dave

allenmehrer

think its worth taking off and giving a good cleaning? i'm running out of options to get my mpg back, theres only 30,000 on the clock so i dont' think its the O2s. i changed my plugs not too long ago so i think i'll go back and check the gaps on those. pretty sure i should have gaped them to 0.055, sorry for the random thoughts, i'm just lost.