Hi, I have a 1996 dodge ram with the 5.9 in it. I just bought the truck about a week ago. The CEL was on when i bought it but it seemed to run good and figured it was just a sensor or something.

After being on the highway for about 5 min the truck started to lose power and backfire through the intake. This seems to happen every time I drive the truck, it runs good for the first 5-10 min then starts to backfire and loose power around 2000RPM, If I floor it for a few sec then the truck seems to run good again for a few min, then the process starts all over again.

Any ideas what could be causing this or what things I can check.

Things to note: the prior owner put a new cap and rotor on it and replaced the spark plug wires. Also I had the code checked and it came up with P0032.

Also is it possible that a vacuum leak could cause this? I noticed there is no vacuum to the switch on the transfer case but I do have vacuum up in the engine bay where that hose connects, so I believe it is just a bad hose, I will be replacing that tomorrow.

Thanks for any help.

 

https://dodgeforum.com/forum/dodge-r...s-section.html

 

Clear the code and see if it comes back...

since the wires were just replaced, start off with making sure the they're routed per this TSB: http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm

And welcome to dodgeforum, it would be helpful to everyone if you would put all the info about your truck in your signature, which can be edited under the "User CP" link at the top left in that black box.

 

And check the plenum thread......

 

welcome to DF. you've come to the right place.


edit - oops. heavily editted. i missed the CEL.

my first guess is bad front O2 needs replace.
http://www.obd-codes.com/p0032



second guess is clogged cat.
third guess is cam position sensor, inside distributor cap.

to test the cat theory, temporarily remove the front o2 sensor and tie it safely up away from the hot exhaust. this creates a temporary pressure relief. take it for a test drive and see if its any better. the mission O2 will cause some other CEL and running rich or lean, buts its still a good test.

 

Thanks Matt.

 

I unplugged the pre-cat O2 sensor and reset the check engine light. Took the truck for a drive and it seemed to have a little less power but I didn't notice it doing the same thing it was before, so maybe it is the sensor.

One more thing to note, I've been noticing kind of a rattling sound when im driving and stepping on the gas but it goes away as soon as I let off, today I noticed the same sound when I was just sitting in the parking lot if I revved the engine a little bit. I had my gf step on the gas a few times while I listened underneath the truck and it sounds like it coming from the cat, so I'm guessing that may be the problem.

If it is the cat would that cause the symptoms I described before?

Also I was thinking about just putting a straight pipe in its place but have to do a little searching on here and see what kind of luck other people have had doing that, eventually I would like to make the truck dual exhaust.

 

with the truck off, hit the cat with a rubber mallet or something of that sort and see if rattles. If it does, the cat is toast. Don't replace the cat unless you've fixed the plenum gasket (if it has actually failed).

 

I went and knocked on it, and sure enough it rattles. Now I'm faced with the decision of if i should straight pipe it or replace it with a new cat.

I havent checked the plenum yet because I dont have a little mirror to stick down there and look but hopefully next weekend I can get around to that. If the plenum gasket is bad will it cause any damage to the engine If I dont get it fixed right away?

 

did you temporarily remove the front O2 yet to check for improvement. if not, do so.

after that, i'd start by saws-alling the pipe right behind the cat and gutting it. you can reconnect the pipe with a connecter on the proper size from any parts store and a couple of clamps.

remove both o2's to protect them from harm.

avoid the pinging; its bad for the engine. when you lay into it and it pings, back off the gas until it stops pinging and live with it until you're ready to tackle it.