Then go ahead and buy two cans of MCCC from the dealership and run them. It'll cost you like $13 tops. It'll tell you if it's build up or not. With the leaking plenum, it'll just gunk back up again faster.

Youcan do the swap, and fix the plenum at the same time, and if you're still having a problem at least you've got upgraded heads and a fixed plenum gasket.

What replacement heads are you looking at running? Hughes has a bare set for about $275a piece that supposedly outflow the RT's.

I'd start first though by pulling your fuel rail and injectors and give them agood cleaning. Just take the O rings off before you clean them or the rubber will dry out and break down from the chemicals. You can spray out the fuel rail with carb and choke cleaner. The injectors can be cleaned as mentioned above. Just be careful with the temps of the cleaner in the sonic bath, I burnt myself last time; it can get HOT!

 

I will try the MCCC stuff, but I thought that the seafoam would do the same thing, is that not correct?

I was honestly looking at some remanufactured heads on ebay, roughly $400 for the set, im kinda house poor and in debt already.

The fuel rail isnt going to have anything to do with the compression, right? I am just trying to isolate issues here.

BTW, I have the fuel line disconnect tool, but I am not sure how it works, gotta tip for me?
Dont I have to relieve the pressure first, and how is that done?
I think I figured it out, just wrap it around the line and push up in there, correct?

 

Pull the fuel rail. If you read the thread about my engine in my sigline, you'll see that my fuel rail had a bunch of junk in the back and a few of the injectors were clogged shut. That could be part of the problem with the fuel rail. If you can't get the numbers up on #8's compression, I suggest re-ringing that piston. Worst case scenario, you may have to pull the head as you could have cracked valve seats, which would account for compression loss and misfiring.

 

I do plan on doing all the fuel rail stuff and cleaning the injectors when I do the rest of the work, but you guys think I should do that first and run the mccc? stuff through it and recheck compression?

Im really trying to do everything in one shot, dont have alot of time and will be moving soon.

Re-ringing that piston is above my comfort level mechanically speaking, I wouldnt mind doing it, but not without some hands on assistance.
The compression on that cylinder is fine technically speaking, the others are high, so doesnt it make sense that its the heads causing the high compression and perhaps a leaky gasket or cracked head causing the low reading on #8?

Thanks everyone.

 

So I just read your engine rebuild threa VWandDodge, and something Steve said caught my attention.
Theheads are prone to cracking, especially between #7 and #8 due to exhaust heat.
I had a plugged cat, so I am sure my temps were WAY higher than they should have been and it makes sense that the heads have cracked and thats why my compression is lower on the #8 cylinder.

 

Interesting, threw another code this afternoon, sure seems like I throw more codes leaving work than anything. Maybe something to do with it being cold when I stop driving?