Factory only has one cat. (except cali trucks) It's a big round cat.

 

huh i guess i just assumed there was 2 on the truck. but its definitely not aftermarket haha its a tiny little square one i believe its a hi-flo. good to know though

 

If it doesnt have 2 pipes going into the cat, and the cat should be the size of 12 pack (roughly), then it is not factory. If it has been changed, and it failed again, your plenum is probably blown or you have a bad o2 sensor. I'd almost certainly change out the front sensor anyways because if it IS clogged then the sensor has likely been glazed from heat and will respond slowly which isn't good either.

 

Very easy fix here...

5.9 99ram2500

CONDITION-
Cold start - idles great. Once warm, idle drops and a loud hissing sound appears, idle becomes rough and sometimes it stalls. At this point the enginge is running rich from lack of air causing all kinds of bad things...

PROVE THE CAUSE - With hissing present, put your finger over the idle circuit. If this tells you the noise is coming from the idle circuit, then your idle circuit is dirty with carbon build up.

FIX - (worked for me) With the engine off, spray a teaspoon worth of TBC in the idle circuit opening. Give a couple a minutes and start it up. It worked on the first try for me at128,000 miles, although i did it one more time for kicks. Did no harm the IACM


AUDI 5000 G,
DBoftheyear

Edit- A simple cleaning did NOT fix this. However, restarting the truck after it has warmed stops the sucking and idle issues. Maybe 02 sensors? Need to check signal...

 

I ended up replacing the front and rear O2 sensors. Truck worked like a charm for about half a day, then while sitting in a car wash, the truck jumped up to about a 1500 RPM Idle and would not go down. I shut the truck off and restarted. Truck started with the check engine light coming back on and barley able to limp out of the car wash. Going home, I had fluctuating engine power and in would die at a stop. I had also replaced the clutch solenoid sensor and transducer which solved some hard shifting problems. Now I don't know what the heck is going on. TPS maybe??

 

Check the MAP sensor and the crank position sensor, either one going bad can cause the problems your having.

 

I had a 97anvenger limp after a car wash once, only second and rev. Dried out over night and was fine. That was a relief.

 

Got the truck back to O'reily's and had them read the code. Turned out to be the TPS after (which I'm so glad because that crank sensor was in a bear of a spot). The problem though was I had to go through 3 sensor replacements before the problem was fixed. The first two they sold me were defective. Not sure how long this one will hold up but it's fixed for now. The front O2 sensor was the fix for the original problem in my post.

 

At least its fixed...... if the current TPS fails too soon, go to the dealer and get one.

 

When you say put your finger over the idle circuit, are you referring to the IAC electrical connection to the IAC? If so, I would assume you mean spraying some TBC on the connection itself in an attempt to clean that connection?