OK, so I bought someone else's headache, and am trying to see if I can salvage a bad deal. . . .

1999 Dodge Durango
5.2L V8

Throwing multiple codes, incl:
P0720
P0300
P0301-p0308
p0123
P0308
P0204 and others randomly.
Engine clearly missing on at least one cyl most of the time.
Other random problems such as cruise control, and
gauge fluctuations. Problems with idling, and starting when
cold (probably another issue but possibly related).

Terrible fuel economy of course, and has been known to shut itself off, apparently when it was feeling moody that day.

My inclination is to send in the Computer to autocomputerexchange to be rebuilt before doing anything else.

Compression is supposedly fine, new cap, and plugs seem fine. I had the intake manifold gasket replaced. I'm just kind of hoping that the computer rebuild may solve some of the issues.

I also get the feeling that the idling issue is related to an A/F sensor issue, but the missing cylinder issue seems more important right now.

Any thoughts? Anything I should do before throwing more money away on the computer rebuild? Am I missing something obvious?

Thanks for the help!

 

you said you did a tune up, what plugs did you use? champion copper core plugs are the best for these trucks, if you put anything platinum in you wasted your time and money as you have to replace them again, they are KNOWN to cause misfires, also make sure you gap the new ones to .040, they DO NOT come pre-gapped.


this sounds to me like a problem with the output speed sensor on the drivers side of the trans, $20 part iirc, but it could also be related to a bad rear wheel speed sensor which is located on top of the rear differential

this would mean a bad tps which is located on the throttle body and is not difficult to change.

this could be a bad injector, loose wire in the loom and could also be partly responsible for the misfires




however, with that many codes i would lean towards needing a new PCM and then going from there, any codes which come back up can then be dealt with at a later date. I also bet if you fix these problems your fuel economy will be back where it belongs.

also dont buy a reman unit, they are known to fail quickly and then you are screwed into buying another one, whitewidow00 has a place that sells new units pre-programmed to your truck

 

I'm thinking a coil as well for all the missing.

TPS

Trans output sensor

Possily related to spark, however it could be a bad injector.