Rough idle and strong hesitation at various speeds. Check engine light read bad downstream o2 sensor. Replaced the sensor and still runs rough. Also CE light still on. Going tonight to have it read again.

Flushed the fuel intakes and installing new plugs this evening. Also have a leak in the muffler.

I would think the two are related, but driving with the hesitation is almost impossible because I have to slowly accelerate.

Suggestions?

 

Welcome to DF. Will move you to the correct place.

For future reference:
https://dodgeforum.com/forum/dodge-r...ead-first.html

 

Did you clear the codes after replacing the sensor? What brand did you use?

Des it idle rough right at start up?

A couple of things:
- downstream O2 sensor only measures cat efficiency. Just replacing the sensor likely won't impact anything.
- O2 sensors only kick in after the engine gets out of open loop (108 degrees, IIRC) if it has problems right off the bat, it's probably not O2 related.
- rumor is that our trucks don't like Bosch O2 sensors. Stick with NGK.

I would wonder if the cat is still good. HeyYou has a good quick check: remove the upstream O2 sensor from the exhaust and go for a drive. If the truck runs better, cat is likely clogged.

If cat is clogged, find out why or the new cat will clog too. A lot of problems get traced back to a bad plenum plate gasket. Read the plenum sticky thread at the top of the 2nd gen ram forum.

Good luck! Let us know what you find.

 

The o2 sensor on my truck kept going bad with the check engine light. Fixed my plenum now no oil is burning so o2 sensor no longer bad may fix rough idle as well since the o2 sensor wont be trying to compensate. Worth a shot either way. Look down the throttle body at the bottom plate see if it has oil on it or stick a magnet through tb and see if it sticks.

 

We'll, I removed the upstream O2 and it still idled rough. Just replaced all spark plugs of which all were considerably worn with carbon deposits. Took the TB off it had a lot of deposit. Cleaning it up now. Will probably go ahead and replace the Plenum Gasket since that is fairly cheap. Keep you posted.

 

Don't just replace the gasket, else you will be doing that job again. Need to address the underlying problem as well, the bolts that hold the steel pan to the intake are too long. Get shorter bolts, or, cut the nipple off the end of the stockers, or get the plenum plate from hughes, or ebay. (ebay is preferred.)

 

Should be able to see pooled oil in back of intake with TB off.

 

I didn't go the plenum route because after taking the TB off I couldn't see any signs of pooled oil. After TB cleaned and new gasket still running rough. At this point I'm thinking clogged cat unless anyone has any other suggestions.

 

Unscrew the front O2 sensor from the cat. Go for a drive. See if it runs any better. (it will be louder though....)

How old are your plugs? Wires? Cap/rotor?

 

Leak in the muffler will have nothing to do with the problem you're experiencing, so don't worry about that. You need to figure out why the check engine light is still on before trying anything else...I would look real close at that upstream O2 sensor and the cat. When you removed the sensor, did you unplug it as well or only unscrew it from the pipe? you need to unplug it all the way to eliminate that as a problem. if the truck still runs like crap with the sensor removed and unplugged, then the problem is somewhere in the engine bay.