Ok, so today I replaced the plugs, wires, and IAC valve (low idle and stalling). Started it up and it ran fine. Then after I drove it for a while it started chugging roughly and smelled like rotten eggs. I looked under the jeep and the cat was glowing red and the engine stalled. Now it wont start. What would cause this?

did the new plugs and wires short out the coil causing unburnt fuel to end up in the cat?

Help please! this is my daily driver!

 

tested the coil and it is good. any other suggestions?

 

would a clogged cat prevent it from starting?

 

if the cat is clogged then the engine will not run or run rough. Most of the time the honey comb inside cat will break up into pieces and will let exhaust trough. If your glow then it is good chance that sealed the exhaust. Time to replace the cat.

 

I think i just got the distributer wet and that messed with the spark. I let it sit over night and it fired right up and runs great now! Thanks though.

 

A wet distributor won't cause the cat to burn red hot.You need to trace the problem before it leaves you stranded.I would replace the cat even if it runs fabulous now.It's turning red for a reason and it's not to mess with your head .

 

 

I'm ordering a high flow cat and catback section. But what would cause the cat to do that other than being clogged? I have a crack in the exhaust manifold which being replaced. Could that cause it?

 

It is common for 4.0 to have manifold crack as the cat transfer vibration to manifold. I had crack too. After welding the manifold, I put flex pipe between cat and manifold. That should prevent future damage. The cat absorbing the exhaust carbon and with time it start cracking and clog the exhaust. You will experience of power loss and excessive fuel consumption. The O2 sensor it is mounted at the end of cat and I would recommend to replace too.

 

Thanks a lot. I will defiantly do that.