I have a problem with my RAM 1500. 2001 Quad Cab off road 5.9L truck.

This has been going on for a couple of years. (I use the truck for towing and hunting only, uses too much gas, and a 800$ toyota doesnt).

Heres the current symptoms all of which appear mostly intermittant and are worse after towing:

Random misses, rough idle. Intermittent p300 p305, p308s. Hissing from the exhaust when in one of its fits, this goes away when I drive a coupe of tanks when not towing.

History of changes to try to fix the problem (all in the past 2 years and 6k miles).

2 coils
2 cap and rotors
2 sets of wires
3 sets of plugs.
Both o2 sensors replaced.
Multiple tanks with fuel injector cleaners.

No other codes than the misfired codes above.

I am leaning toward the catalytic converter being pluggeds. The majority of miles on this truck are towing either a 6,000 pound camper, or a car trailer with other cars and .5 ton pickups or a 540 bobcat or gravel, dirt on the trailer.

I cant find any vacuum leaks, and no other codes are showing.

The truck now has 770000 miles on it, it started this stuff at about 71000.

Does my diagnosis sound right? Will the
http://www.streetperformance.com/par...190-23285.html cat at this link work?

 

It doesn't sound like a bad cat to me, but I could be wrong. When my cat went bad there was a rattling noise at idle that was very noticeable when you stood near the right side of the truck. To know for sure if the cat is bad, you would have to take it to a muffler shop or something where they can do a flow test. You can also tap it with a hammer with the truck off to see if there is anything loose in there. Also if the pipe right before the cat is a lot hotter than right after the cat, it's probably clogged.

The cat in your link is the one I have on my truck and I couldn't be happier with it, it was a perfect fit. I'm not sure what year your truck is but it worked on my '99. Hope this helps, good luck.

 

Sounds like plenum and Cat to me.

 

I just borrowed a ir thermometer. input throat of the cat is 289 degrees. output is 291-297 degrees. shouldnt they vary by 50 degress, and is that difference farenheit?

 

I see you posted on a cat thread about cats.

This is the one I think I need, and I have your truck....

http://www.summitracing.com/parts/MPE-94309/

01 quad cab 1500 off road 4x4.

The measurements I got off my cat are 3" input, and 2.5" output. I dont see any air injection at all and the o2s are before and after.

I am pretty sure I need a new one, I am throwing random misfires, and have a random hiss.

Also a temp reading shows less that 15 degrees diff between input and output of the cat. 290 input and about 299 output.

Is the above one the one you used? it looks like it has 3" out as well s 3" in. I guess I need to squeeze it down to 2.5 when I cut it into mine?

 

Only get that one if you want to pay extra for a mirror finish. Unnecessary unless you have a show truck.

The MPE-94109 or MPE-94009 are what most go with on here for 1999-2001 model years. 94009 is 3 inches longer, thats the only difference.

Yes, you will have to use a reducer if you keep the rest of the exhaust stock after the cat.

Whatever you do, don't let an exhaust shop tell you you have the older style 2in/1out converter with the O2 sensor on the top. Most will try to tell you that and swear thats what you have, because thats what their computers tell them.

 

Thanks. Other than length, I cant imagine why I would have an issue with either.

a bud is going to make me a reducer, which is only about 2-3 inches long. Whats the best one of the two for fit considering? The longer one?

 

I don't think it will really matter. The stock cat is a huge sucker, it is almost twice the size of either of those Magnaflows.

 

So I replaced the cat. I will have to do some more work to close up a couple of leaks. Not easy welding where you cant see.

Anyway after 1 tank of gas, and when I dropped below .5 tank.. bingo, the codes are back, all three p0300, p0305, p0308.

Now what?

 

I should add that the oil consumption is nill/zip/nada on this truck, and the plugs are always nice toasty brown, very light brown even.