Just joined after searching threads for my issue. I'm looking for help with a 2003 Dodge Ram 1500 quad cab 4x4 rough idle issue with 5.7 hemi.

Truck rolled 200,000 miles last weekend during a college move-in trip from OH to SC and back. Made the trip down no problems - stopped after 6 hrs and finished 2nd day in 4.5 hrs. Drove straight back 10.5 hours last Sunday.

We were about 1.5 hrs from home when truck starting choking and sputtering. Really rough idle - engine light came on. We were 84 miles from home and I was concerned if we stopped for the night it might never go in the morning. We continued on home, arriving after 1 am and the truck DIED in the driveway.

That was last Sunday, since then I have change all 16 spark plugs. Truck still has very rough idle. Max rpm is 3500-3600 with foot fully on the gas. Won't go past 3600. Truck dies out completely whenever I stop reving it.

After reading various threads - I'm seeing possibly catalytic converter issue, possible 02 sensors, etc. etc. etc. I'm thinking it's most likely the catalytic converter which has never been changed - I'm the original owner.

Cat from dealer is $1100 and has to be ordered. Auto parts stores appear to only have 2WD Cat. Summit Racing said there doesn't appear be a magnaflow cat for 4WD.

Since I don't know what the problem is, I thought I'd ask your advice before I start more money and time at it!!

What are your thoughts. What direction would you go to next?

 

Found that I had the code P0032 so I bought the 02 sensor. Managed to remove the O2 sensor in front of the CAT late last night. I quit around 11pm and am waiting til 10am to give neighbors a quiet morning, before starting the beast. I'm expecting it to be pretty loud.

Hoping to see some improvement after installing the new O2 sensor. Would love to avoid replacing the CAT at $1100 plus but still pass e-check which I'll have in March.

Surely there is some way to avoid that dealer price. Has anyone with the 5.7 4x4 replaced their CAT? What did you replace with?

Also, I've had wife reading more threads. Found info on rev limiter and "limp mode". I didn't know about either of those. Am I correct in assuming the rev limiter is would be why I can't go past 3600 RPM? I'm not sure if I'm in "limp mode" or not, but the description sure fits!!! How do I know?

 

2003, wont idle, shakes and sputters, have to hold gas to keep rpms high to keep it alive all sound like a broken valve spring

 

New O2 sensor installed. No change other than the P0032 code is gone.

Cough, spit, sputter, dies! Frustrated!

Should I post this somewhere else?

 

did you read my post?

either do a compression check or pull the valve covers and check for a broken valve spring

 

Do hemi's have dual valve springs?

 

Ive had this issue before, but on my o4, was a broken valve spring. after it was replaced ran like a charm. Deffinetly would check into it being a valve spring problem. Symptoms youve had are exactly the same as mine.

 

Dual as in one for the intake valve and one for the exhaust valve? Yes.

And I have a complete set of Miller tools for sale which are needed to pull and change valve springs if you find that to be the problem.

 

dual as in a retainer spring within the primary spring

 

Nope.