First things first: its a 1998, 5.2, 113k, Hughes plenum, SCT tuned, new cap and rotor,fairly new plugs and was running like a champ all last week. So two nights ago I decided to do some off roading with some friends and long story short on the way back just driving on the dirt road, my truck began to sputter and barely run with the pedal basically to the floor. Frantic thinking i quickly stop moving throw it in park and it dies on me, takes a couple turns of the engine to get it started and fires right up but will only stay alive if I keep my foot on the gas. At this time the truck is running like crap. I just kept it alive until friends arrived with help roughly 5-10 minutes later, now at this time I was only keeping the RPM at roughly 1000-1800 rpm. Nothing much, and engine temperature was steady. (180 t stat). As they are looking under and all around while I'm keeping it alive, they notice my cat is GLOWING bright orange. I tell them to keep it alive and I observe the same situation to be the same. I have no idea why that is?

Approximately 4 months ago I had the Exhaust completely replaced. A brand new cat, and a flowtech muffler for a little sound. It was all good and great until I started to notice a rotton egg smell quite often when I would get on it. (coming close to 3k rpms, nothing too special). Now this was very puzzling to me because I am led to believe that the cat is now bad, but I was told that it just has to break in, so I just dealt with it, but maybe the problem has gotten worse.

Today's investigating was that my wires are bad due to a mud/water combination getting into the cup type heat shield that surrounds the spark plugs in the block. I took the wires off of a couple plugs and no change in pitch or rpm of motor, some had a significant change in rpm. I will be replacing the wires tomorrow in hopes to solve my running rich issue. Thank you.

 

Glowing cat? Rotten egg smell? Sounds like a bad/clogged cat. Remove the pre-cat o2 from the pipe and see if if runs better.

 

Thats exactly what I was thinking, but the dam thing doesn't even have 3000 miles on it.. I have no idea.. I'm going to have to try that test tomorrow.

 

Rotten egg smell is from sulfur in the gas and your probably running pig rich, unburnt fuel burning in the cat possibly. Upstream 02 sensor could be suspect also.

 

I just calculated my gad mileage city driving as well right after the hughes plenum, SCT tune, new plugs, new cap and rotor, 180 t stat on 87 gas and I'm getting 11.1 mpg. I figure thats not so bad for 3:55 rear gears and 33 inch tires on 16 inch rims.

 

I have to agree, I believe it's a bad cat. running rich can cause the cat to go bad, you may have just gotten a a bad cat, or it could be a combination of the two. Remember, everything these days is mass produced and quality control is not what it used to be, so there is always a possibility that you got the one that slipped through without a good quality control check.

 

Thats exactly what i had figured, it just fustrates me, this whole situation.. But thanks for the input, your definitely right about that.

 

Even though you only have 3,000 miles on your exhaust it doesn't mean your cat can't of gone bad. If you have been running rich all this time it could be clogged. I had the same thing happen in my Jeep so I would for sure get your pu$$y looked at.

 

A gynecologist might be a bit expensive, and getting an appointment could take a few weeks. I would just find the source of the clogging and then replace the cat.