Intake Plenum

Cory281

Member
Jun 6, 2004
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Hey guys, yesterday I took off my intake hose to get my air filter out and I was looking at my throttle body and I turned the butterfly valve and suck my finger past it into the plenum and there is a ton of black stuff all over in there. I've noticed the car feels like it has lost power, so I have a few questions.

Why is this happening?
How can I clean it?

I'm kinda thinking maybe it's running rich? I don't really know, thanks for the help! :SNSign:
 
There would be a sooty carbon (black) buildup in the exhaust if it were running rich, not the intake or plenum.

Do you have a K&N filter or anything? They let a bit more dirt through than a normal air filter. Its not uncommon to have a little bit of dirt in the throttle body or plenum.

Check and see if your PCV hose, intake air temp sensor, or the IAC hose is loose and letting unfiltered air in.

You may as well jump on the band wagon and run some Seafoam through the motor if you are comfortable doing so... if theres alot of buildup in the combustion chamber that will take it out.
 
I would recommend that you take your TB off and clean it with some 'throttle body cleaner'. Not carb cleaner or brake cleaner .... TB cleaner! I know, Ford says not to because of some "special coating" but you can just use a rag, spray cleaner on the rag and wipe that crap out.

When I replaced my intake I had to take all that crap off anyway ... mine was nasty as hell too. I cleaned it as described and it helped substantially. They just get nasty over time ...
 
I think I it is in my exhaust tips too. Everything is on tight and I do have a K&N filter. The weird thing is that the throttle body is really clean, all of this crap is in the plenum. Tomorrow I'm going to tear it apart and clean it out, so I should use throttle body cleaner to clean the plenum?

Oh and I did run some sea foam in it a few months ago, should I give it another go?

Thanks.
 
If your taking the TB off to clean it, may as well take the plenum off to clean it as well. TB cleaner will work fine on it.

If you just did a Seafoaming I wouldnt do another so soon, probaly not much back in there. How much came out last time?
 
It smoked about 2 blocks maybe 3 down the street and that was it. The plenum is the dirty part and the back of the throttle body. The front side of the tb is clean.

Thanks for the replies, I'm going to clean it up, I'm going to the track this Friday, anything else I should check up on?
 
This is a combination of EGR soot and oil from the PCV system. The modular engines pull quite a bit of oil (about 1-2oz. a week is normal) plus the soot from the EGR.

You can clean it, but without an oil seperator (and weekly emptying it) and blocking off the EGR it'll just be sooted up again in a week.