Is it normal for there to be residue in the plenum plan. It has been replaced after i bought last august, when it was bad it pinged bad going up hills and let out a puff of smoke out of the exhaust. Right now it does not do any of that, i just figured that i'd look down the throttle body and check, and there was a little residue on the bottom of the pan, it was not pooling in or anything, just looked like brownish residue, a very little film of it, i could not see any leaks. Is this residue normal???

Thanks

 

I have been fortunate enough not to have the plenum problem yet, but I have something similiar as you described. My truck runs great, no pinging, etc... My theory is that a previous owner cleaned the throttlebody with it installed on the manifold. I beleive the debrise I am seeing is the deposit that was washed down into the plenum pan from the throttlebody cleaning, the throttle body cleaner having evaporated long ago leaving just the debris behind.

It could also be junk that is coming in through the air filter, and slowly builds up over time (if you have a bad airfilter, leaking air cleaner box, etc...)

I would not worry to much about it unless:
-truck starts to run bad like people report with a leaky plenum,
-buildup appears to get worse
-buildup appears to be loose or in some free floating state

 

It actually looks like a alot of junk, black specks and stuff, kinda like dirt and stuff like that, but there is a brown residue, not pooling at all and not showing any symptoms of a blown plenum. I do not think it smells like oils at all either.

 

Ya, that is pretty much how mine looks. You might be able to clean it with throttle body off, access is a little better. I have been afraid to clean mine because I don't want to loosen it so that it is free to go elsewhere. Best way to clean it would probably be to take the manifold off, in which case you might as well upgrade to the better plenum fixes you can find posted on this forum.

Next time I have my TB off for a cleaning, I will take a picture before I put it back on.

 

Crankcase gases are sucked through the PCV valve and coat the inside of the intake. This is normal. Pools of oil are not normal.

 

actually yeah, that is right, i forgot about the PCV valve. Today i looked thought the plenum blew, and i thought i was gonna have to fix it, and this weekend is not a good one, considering i live in MA and the Pat's are on saturday. When i saw the residue, i thought it has a good chance on eventually geting worse, scared the crap out of me.