Plenum is horrid

[Derek3.4]

This is on a 3.4. Alright, so I've been having the dreadful SES light come on when I decelerate from about 55 or 60 mph. I took the EGR off and couldn't seem to see a clog or anything. So I figured I would take the throttle body off to clean it up since its about black from build up on it. Once I took it off and looked into the plenum, DANG! It's almost completely black inside of there, real nasty looking. I'm hoping to get the plenum off today or tomorrow to try and clean it out some. I figured the port where the plenum connects to the tube for the EGR is closed off due to all the gunk in there. Any advice for taking the plenum off and cleaning? Thanks.

[Andy H]

Re: Plenum is horrid

well I can tell you when you get the plenum off to use brake parts cleaner on it and it will clean right up! I tried using sea foam deep creep on mine and it didn't hardly phase it. Also, stp throttle body and intake cleaner worked pretty good.

[tkoforpresident]

Re: Plenum is horrid

get a sturdy pipe cleaner or a bent coat hanger. you will need it to pry loose all the built up carbon in that egr passage below the plenum. then maybe some compressed air to blow it out will do the trick.

getting the plenum out is a pita because all or most of the bolts are far under the cowl. make sure you torque the bolts right when you put it back on, and maybe consider getting a new intake gasket while your at it.

[cam98aro]

Re: Plenum is horrid

get your hands on some BG throttle body cleaner, that stuff is amazing

i use it to get the tar off of my exhaust and just a tiny spray and it instantly starts to drip off and shines up the chrome great

never used it for an intake, but i can imagine it would work just as good

[ssms5411]

Re: Plenum is horrid

Deep creep it and seafoam the hell out of it.

[Derek3.4]

Re: Plenum is horrid

thanks for the input guys

[Derek3.4]

Re: Plenum is horrid

So I can't find any clog, I'm thinking it's in this passge. Sorry for the bad image, I found it on the net and used it for a visual. I marked it as the line inside the circle.

[Derek3.4]

Re: Plenum is horrid

anyone have any tips to reach that little area?

[tkoforpresident]

Re: Plenum is horrid

i see no pic

[Derek3.4]

Re: Plenum is horrid

hmm... i see it on here plain as day.
Maybe I can explain it. Probably not going to be a very good description, BUT, her it goes...
So, looking at the EGR, right under it, there's tube that goes down under the EGR that connects to the exhaust, has some way of a connection to the tube that goes to the plenum. Its in the connection between between the plenum tube and the EGR tube. Hope that makes some kind of sense....

[tkoforpresident]

Re: Plenum is horrid

i see it now. No, i don't think that is the cause of any clog, but it wouldnt hurt to spray some carb cleaner in there.

you might have a bad digital EGR. you can get used ones in good cond. on ebay for like 40$. But honestly, i wouldn't worry about the EGR, it does very little that is worthwhile for you to want to fix it. Most people delete theirs when they find the opportunity to.

[Derek3.4]

Re: Plenum is horrid

I already replaced it and it didn't do anything, but if I take the egr off and plug the exhaust coming up, there's nothing that goes through the other tube to recirculate into the plenum. I just want to get some better mpg. I changed the plugs and filter and it didn't do anything. It's horrible.