i just discovered mine is bad. i only took the throttle body off cause people told me to check for oil down in the kegger. i think i have a even layer of dried up oil in the bottom. how does this effect the truck? and do i just replace a gasket or do i need to replace something else too? i kinow this is prob a stupid question, but...... it is what it is lol

 

Lotsa threads on this, and a DIY on the FAQ forums as well. but, in a nutshell, blown plenum will give you spark knock, fouled plugs, poor performance, bad fuel economy, excessive oil consumption, and a few other fun things besides.

 

and no you cant just replace the gasket, it will blow out again.

 

If it's let go long enough carbon buildup could cracke heads, interfere with piston travel potentially causing compression problems, clogged up catalytic converter, fouled plugs, who knows what else?

 

clogs plugs,cats,poor mpg poor performaces,causes missfires,cloggs 02 . its a good idea to change out ASAP to save you lot of money elsewhere