Yes its blown, ive heard of them blowing before 20K...and the dealers way to fix it, is retune the PCM to cope with the leaking plenum AKA "Deathflash"

 

Still calling B.S. on your MPG numbers. Either you haven't adjusted your speedo for your tires, or you aren't doing your math right. And you must drive like an old grandpa.

Miles driven divided by how many gallons are put in at the pump.

 

Ok, so after 3-4 hours of pulling the intake manifold off another 9-10 hours cleaning it and getting old gaskets off and also cleaning the mating surface on the heads I have determined that I miss the valley pans simplicity lol. Also, the plenum gasket appeared to have already been replaced with the same felpro gasket I got, I'm going to do the hughes kit but after I get back to NC and have my garage back instead of working in a parking lot. The plenum gasket appeard to be good although very stuck in place. The problem I did find however was that the two manifold gaskets were, well lets just say no longer gaskets. Most of the gasket just dissintegrated after trying to pull them off. It's all back together now but I am having a bit off another issue. It seems almost like a miss, I pulled injectors since I lost my fuel line tool and I think I may have had a couple not seat right or something. I'm losing even more speed going up the same hill now but It at least feels like a v8 and my exhaust is a lot louder which I think the 1/8 inch of carbon in the manifold had something to do with that. Also 13 MPG was average from NC to California and No my speedo is not adjusted for the tires, but I use my gps speed and odometer and that doesn't need to be adjusted. I still think a new coil is in order and maybe some new injectors because most of the injectors had a clean spot where the gas hit the manifold but a couple showed no signs of firing even tho no codes are coming up. anywho I'm super tired and goin to bed I'll check for responses tomorow

 

Ok, so I am officially an idiot! My miss was actually being caused by me knocking off the #2 cylinder spark plug wire at the distributor. I feel pretty dumb after thinking that was the injectors. I do notice a bit more power which I think I can attribute to cleaning the manifold and getting some more air flowing. I think my main problem is 1. My tires being pushed by an underpowered engine. and 2. My 3.55 gears. I have been looking on ebay and I can pick up some 4.10 ring and pinion gears for 50 bucks a pop, is it worth it?

 

Yes, unless they are crap.

 

Ok then, how bad is setting backlash and doing the shims and all that? I feel pretty comfortable with tearing my engine down to nothing but the crank but when I move from the powerplant to the drivetrain I get a little nervous mainly because I've never done it before. If it's something that I'm gonna want a pro to do instead of doing it myself I think I may just opt for going down to 265's if not 245's and get a new set of rims so I can throw on the big tires to go off roading and put the little ones back on to maintain drivability.

 

If it were me I would take it to a shop and have them put the gears in. I don't think that it's extremely difficult but, it's tedious and if you make a mistake in setting the gears up you'll drive a couple of feet and then kabloom. Your buying a second set of gears.

 

Bigger tires make the odometer read lower=getting better mileage than indicated. Correcting his speedometer would only make the mileage look better... It's the 5 speed, plain and simple.



Basically, your truck sounds normal, too big of tires with too tall of gears, there's nothing wrong with downshifting and turning higher RPMs, it's better than lugging it. Keep it out of 5th under 60 for while and see what your MPG does, it probably won't change and may get even better, either way it'll be better to drive.

 

So I just did a pretty sweet trade with a buddy from work, got his hypertech, and bed rails for my toolbox and he is saying he might trade me his 33's with backspaced rims for my stock rims with 285's. probably not gonna help my power issue but at least I'll have some decent looking tires that won't rub on the control arm anymore. I did the regular gas tune on the hypertech and although it's still not where I want it to be having my 4 degrees of timing dodge stole back seems to give it a little kick. It's really not noticeable on the road but off road it wants to take off like no other. Threw some ngk iridium plugs in apparently I forget things because I should have realized my old plugs would be fouled with the plenum being blown out. Now I have a whole new problem I think my rear main is out because oil is drippin from my flywheel cover....not lookin forward to doing that. I really think my best bet at this point is just keep driving till I can make some money sellin it and get a different truck. This time I'm not gonna let the wife tell me no and actually get my power wagon like I wanted to in the first place.

 

are you referring to me? my speedo, and milage is not off btw...