Catalytic converter Cherry Red!!!!
 

I have a 95 F150 4X4 5.0 5 Speed. 186,000 mi. Over the last couple months when starting off cold the engine would sputter (?) and cut out, but after the RPM would rise it would clear up. About a week ago it started to cut out through at all speeds and RPM, hot or cold. I was thinking fuel filter or spark plugs. Maybe a bad guess on my part, but anyway. Tonight I replaced plugs, wires and distributer. I dont know if I done something really wrong but it is worse ( will hardly run at an idle) and after about 10 minutes the exhaust pipe gets Cherry Red at the exit side of the catalytic converter!!!! I tripple checked the order of wires. It is correct! What ****** have I done!! I have never even heard of this. Is the catalytic converter bad and causeing the rough engine running? How did changing sparkplugs and wires effect this and cause the exhaust to get Red? I dont even know where to start next after tonight? Should I replace the converter? Thanks ahead of time for any replies.

Were I you - I'd be looking and feeling all around to find an open vacuum fitting that has no line attached.

Go all around the intake manifold - especially in the back, with an inspection mirror - or if EFI, think about the idle air bleed.

Headers only do that on an extreme low mixture!

If the converter is getting red it is clogged, but your sayin its red after the cat? A clogged cat can caus the engine to have no power.

I would have to say that the catt is clogged up, that happened to me once before, i was pulling out and had no power what so ever and the truck wouldn't stay running at a stop sign, needles to say the catt came off and straight pipes went on..lol but that truck is gone now 'RIP' thanks to a drunk. Good luck

Sounds like you have either an extremely rich mixture, or a substantial misfire, both of which will dump unburned fuel into the exhaust, where it burns, causing higher exhaust temperatures than normal. Out of curiosity, what firing order are you using?

Did your engine temp climb also? Mine started running like that lately the temp guage climbed like crazy. I am thinking clogged cat. I will look if it gets that hot.

Sounds like the Cat.

I had all 4 cats glowing red on my last '93 Lightning when the PIP was acting up. I would also question how the timing was set?

I can see extremely rich mixture (FPR, O2 sensor , ...), or a substantial misfire (PIP), both of which will dump unburned fuel into the exhaust but I do not see how a clogged converter will cause it to get RED.

I was always informed that no power and glowing red cat were signs it was bad (clogged). Im not gonna go against you. I could learn me something new here.

I can see bad timing doing it also.
I have heard it also that a clogged converter will cause the converter to get RED.
But do not understand how a clogged exhaust system will cause anything to get red.

If your state does not have emissions testing, cut off the exhaust behind the catalytic converter. Take a breaker bar or long hard metal object and poke through the cat. Keep doing this until all the guts inside the cat have been broke free. Start the truck and blow it all out. Put in a sleeve and some u-bolts. More power and will probably fix the problem. Had a van with this problem and I just ran a straight pipe. Problem solved.
VT247

timing being off will cause the manifolds to glow if the cat is just glowing its clogged... so either bust it out or replace it with a new one or a piece of pipe

and it causes the cat to glow because the hot gasses build up and cant escape so it will heat the cat and exhaust pipe up so much it glows and can develop leaks

Remove the o2 ahead of the Cat. if pressure there is more than 3 psi, back pressure! If the temp & power returns to normal while the o2 is removed, back pressure. Cat's pooched. This does not address how it got that way. #1. Running higher than 87 octane redundantly. Also, Error code scan results, are your friend!

I remember a guy on here months ago that was pulling his hair out over what ended up being no spark to one cylinder. Turned out that one of the brand new plug wires he just installed was bad right out of the box. It was actually sort of funny to me because when he brought it back to the parts store (I think it was Autobone) he said he got in a fight with the guy at the counter over it, almost a fist-fight, lol. Now that's frustrated!

Soooo, that said, I would do more than just check the order of the plug wires you just put on, I would check each one to make sure you are actually getting spark through them. If you are, I would go with continuing to snoop around the cat being plugged. That sounds most logical at this point and with that many miles on your rig, very possible.