I have a 2000 dodge ram 1500 sport 5.9. I was driving down the road the other day and gave it gas and the truck started bogging, knocking, with no power from the motor. I had to milk it as far as i could out of the middle of no where to get towed. Once pulled over i looked underneath and saw that the exhaust pipe right before the catalytic converter was glowing red.

I got it towed home from AAA.
The next day i went out to the truck and started it up and it ran like ****. Wouldn't idle on it's own for more then 15 seconds. I got word that the cat was bad so i cut it out. Still runs like ****.

Symptoms of the truck are:

no power
rough idle
Loud back fires
sounds like some sort of vaccuum leak

I hooked up a code reader and came up with the following:
P0505- Idle Air Control
P0123- Throttle/Pedal Position Sensor (position A circuit high)
P0108-Manifold absolute- Barometric pressure Circuit High
P1391- Interm loss of CMP or CKP


Anyone have any ideas?

***New Symptom***
A little smoke comes from the Oil cap when the truck is running...

 

I am reattaching the Cat to the muffler after cleaning all the honey comb out. Hopefully will get some back pressure to get rid of the backfire. Will repost more once completed.

But for the other things.. I would love some help.

Thanks

 

have you replaced your plenum gasket? do a search on it

 

i had to reset my pcm after gettin rid of my cat, disconnect the battery and cut the lights on for a few seconds. This cleared mine up but i didnt have all the other problems you are having, let me do some thinkin

 

Changed the O2 sensor.. TPS and all 8 spark plugs... Still wont idle by itself for more then 15 seconds...

The guy next door says it sounds like it's starving for fuel or starving for compression... Says to run a fuel pump test to see if its giving enough to the motor.. or to run a compression test on all 8 cylinders (one at a time, and they should be at 150psi after 3 rotations.) That's my best bet i guess before it gets shipped off to a garage to let them deal with it...

After 200 dollars.. im still aggravated.

 

Thanks for the replies. The plenum gasket seems like ALOT of work for the schedule that im on. Working 7 days a week for a while. So if it's that im going to have to bring it to someone :/

 

Change out the IAC (Idle Air Control) with a new one. Then go from there.

 

if you haven't reset the pcm and cleared all the codes, you need to do that first.
you may have multiple problems, but the clogged cat was probably the most serious. it might have caused other problems, such as cooking the 02 sensor, and the whole clogged cat problem might have been caused by leaking plenum.

your next most serious problem is the backfiring into the intake. this is either a intake valve stuck open, cracked head, or its firing out of time, or else a spark plug wire is mixed up which also causes it to fire out of time. this might be related to a bad cam position sensor (in the dist) or crank position sensor.
or - if its firing into the exhaust manifold, then it might be a burned valve or cracked head.

i'd do a compression test first to see if you have a major malfunction or not, especially before throwing any more parts at it.

 

Checked all cylinders and got over 150psi on each one.. It sounds like some sort of vacuum leak.. So i just brought it to the garage today.. If people are still curious as to what it was, ill post the results in a few days.

 

sounds good keep us posted