I have a 2000 dodge 5.9l that has an electrical problem that I cannot seem to fix. timing is off intake backfires that's gotten progressively worse over the past few months. codes recorded p0305 cylinder 5 misfire I have replaced both crank and cam sensors I really want to know for sure what it is before buying a new ecm. has any one had or has heard of this problem? and what I can do to fix it?

 

Welcome to DF. For future reference:

https://dodgeforum.com/forum/new-mem...-yourself.html

Moving to the correct section.

 

How many miles on it? Have you fixed the plenum yet? (see stickied thread at top of this forum.)

 

180k plus on the truck and no haven't done the gasket would that cause extensive backfire in the intake?

 

I am also new to this site so im not sure where to look for the stickied thread

 

It gives you a vacuum leak, leads to burning a bit (or, a LOT) of oil, which destroys O2 sensors, and catalytic converters. With that kind of mileage, it's a pretty safe bet that it is bad.

If your O2 sensors are original, they can become problematic simply due to age. Also, the morse-style timing chains in these trucks are very prone to stretching. That would tend to retard timing though.....

Check the plenum, and do a compression test. (dry first, then wet) Lets see what the numbers look like.

 

Right at the top of this forum. "Stickied" implies that it will always be toward the top of the first page. Just depends on how many sticky threads there are.

Oh, and a belated: Welcome to DF!!

 

i have yet to do the wet test but dry test as follows: cyl#1 132 psi cyl#2 119psi #3 102 psi #4 100 psi #5 88psi #6 110psi #7 92 psi #8 105 psi i am beginning to think the head is cracked near #5 wet test should provide a little more info

 

also i am having a hard time wrapping my head around the fact that it feels like it wants to shake itself apart while driving shakes so bad it broke my dash

 

100 psi is minimum according to service manual. A wet test will tell if it's rings or not. Either way those are not very good numbers...and it may be rebuild or find a different motor time.
With that mileage I'd guess it's not a candidate for new heads either.