Fuel System Problems, hot Cat

So I have developed a problem with my '87 4.0 Renix.

I was running a mild trail earlier this summer when all of a sudden the engine started acting like an old carbureted engine with no fuel pressure. The engine would increase rpm if I pumped the pedal, but would sputter slowly to an eventual stall going from 1200RPM at starting gradually over about 60 seconds to stall.

I can hear the fuel pump working all the while. Haven't replaced the fuel filter, but will be doing that today.

This hasn't happened again all summer until yesterday when I was on a difficult trail:
http://www.traildamage.com/trails/p...030810&t=Green-tinted water&f=green_water.jpg
I was running solo with the family and the stupid rig started doing it again.

Then, on the road home, to make things more interesting, the cat and pipe to the muffler heated up to an orange color and started melting the padding/carpet in the cab.

I figure I have a computer/sensor issue and am wondering if anyone could suggest the most likely candidates. I was suspecting the TPS with the pumping action helping, but with the cat heating up so hot I am thinking I might have an issue with a sensor like the O2, Engine Temp, or something else that is causing the computer to over do the fuel injection leading to unburned fuel in the cat.

Thanks in Advance!!!
Rob (AKA Rocky Code Head)

Sounds like a clogged cat. Disconnect exhaust.

X2 on the cat.

The sputtering and stalling before was likely your cat taking a dump. Back pressure running into the exhaust. Maybe not a fuel issue at all (unless you checked the fuel pressure).

The recurrence of the symptoms, with the addition of the red hot cat says that your cat has taken that dump.

Disconnect, see what happens.

ParadiseXJ said:

your cat has taken that dump.

Click to expand...

Fresh step kitty litter is all you need! lol How you been?

Or running too rich?
Do you have a cracked exhaust manifold?
I've had similar symptoms unrelated issues.
I have an 87'
Sputtering, bad 4" of fuel line in tank from pump to sender.(doesn't explain your red cat)
When my cat went bad it would be fine when it was cold within a few minutes severe loss of power. I'd have to rev to 3500-4000 rpm to ease off clutch (burn it in) to go anywhere, I had to make an adjustment to cat (beat it with a long sharp stick)

The pedal pumping sounds like a bad A/F issue.
Let us know what you do we'll see if we can help.
Fuel filter would be good to change, get it from NAPA no FRAM

The stalling while running or high idling sounds like a clogged cat. Last time I (or actually my wife) ran into this was my '80 Mercury Zephyr. Would start and run fine, but gradually load up and lose power. Everything gets hotter because the exhaust has nowhere to go, and what little gets through the cat is screaming hot, giving you that warm glow. I fixed the Merc by busting out the ceramic honeycomb, and it ran better than ever. Now, I can't suggest that you run without the cat, but gutting it will tell you if it's the problem, and then you can replace it, to be all legal like. At least nowadays, they don't cost as much as they used to.