You have to physically check to see if the plenum needs to be replaced. Read through this thread, but basically you can visually inspect it for oil, or use the magnet on a stick.
I just took the throttle body off, opened the valve and looked down in there. If you see oil pooling, plenum should be replaced.

 

no cats no problems

 

I'm new to here... love my dodge and this became an issue after loosing oil antifreeze etc... i replaced the whole exhaust but that was just something i wanted done any way. and couldn't figure out my problem and started looking around the internet and found i had all the plenum related problems, so i looked into it some more and found the hughes solution and strongly recommend it to anyone going through this theirs a few videos on you tube i watched to learn how to do my own as im a penny pincher lol. it comes with all the gaskets and a new aluminum plate. i cannot find the link to share. im just saying if you're gonna change it spend the extra cash and get a hughes.120 bucks isnt to bad and itll fix the problem for good.

 

Hello all. I have a problem with my 01 5.2 that I think might it might not be plenum related, but it seemed a good place to start seeing the "symptoms" of one. My engine will randomly drop Rpms to extremely low levels, so that once I lose my current momentum I can only o about 10 mph. If I give it throttle, it will not go anywhere or adjust engine speed at all, it will just stay the same. I'm not sure what a misfire or backfire is technically, but I think my engine does. It will get a bit of a rev then knock and click then cut back almost to a stalling out, then resume it's chugging idleish rpm. The knocking I hear is not what I think you guys are describing as a "ping", it's a deep and resonating knock that sound. The only thin I can get thi to stop, is to pull over, shut my engine off, then turn it back on and upon startin give it a hefty throttle to get te engine high, then it USUALLY goes to normal and I drive off, but sometimes I must repeat this several times.

Now I'm not sure if this I related, but my transmission when shifting between fourth and overdrive will hit this gear in the middle (that doesn't exist cause it's a 4 speed with overdrive- automatic). I will count the shifts from a stop. Hits one, two, three, then four, then after fourth it will shift again, but then I can shut off my overdrive manually with the OD shutoff button, and once I shut the OD of it will kick up into a higher rpm (which is fourth gear). Then I shut it off an it goes back to this mystery gear. I know this sounds retarded, but I swear it get stuck between the gears. At 50 mph my engine is running pretty close to 1500 Rpms, then when I have te overdrive it will be about 2000 Rpms, then in the mystery gear it will be at about 1800 Rpms. Sorry if this secon paragraph isn't in the right place on here, thanks everyone for all your help!

 

Check your plenum, and see if there is any oil.

For the second part, what you are seeing is torque converter clutch lockup. Completely normal behavior.

 

I checked my plenum, and it has the normal bit of oil spew the photos show here on the forum but does not seem to be pooling or have excessive deposits. So if my plenum is not blown, what could be causing this chugging in my engine? It is becoming more and more frequent every week..

 

Your plenum is blown. Did you take the throttle body off or just look down the butterflies? It likes to pool in the back. Hard to see.

 

I'm going to fix plenum on next saturday, will pick up the gaskets tomorrow, but forgot to order new bolts. I'll go and see if bolt store down the street has them, I'm just not sure I got the sizes right (been searching awhile from here). Intake bolts are 5/16-18 x 2 1/4" and plenum is 1/4-20 x 0.75", right?

 

You can re-use the plenum bolts, just keep in mind they are too long, so, stick a washer in there as well. Use Blue Lock-tite on those. Don't want them falling out, into the cam area, that would be bad.

 

I'm going to buy a piece of aluminium and make a new plenum plate, so no issues with too long bolts. So the intake bolt size is correct?