Hello, I am new to the forum and my F150 is my son's. It has been running poorly and I sugested that we start with several tune up sollutions such as plugs, wires, and coil. My son changed these out today and when he started the truck it ran worse than before and had a funny rattle coming from underneath. I jacked it up and the cat converter was glowing red hot in about 2 min. This didn't seem right and I was just checking with you to get your opinion.

 

Could be a couple of things. 1. A leaky injector is dumping fuel onto the cat, causing it to glow. 2. The cat was clogged causing things to back up.
Either way a new cats and front O2 sensors should be in order because once they glow red, it's usually game over. Bench flow test all the injectors to ensure that is not the cause also. Then continue the maintenance with a MAF and throttle body cleaning.

 

Thanks Otto, my son says that it is spitting liquid out the back. Could be fuel, he said water but I don't see any water in the oil. If it is an injector it must be dumping lots of fuel into the system. I will have him check this out. Thanks again!

 

They make a lot of water when started up. If it doesn't have a sweet smell and very foggy your ok probably with the exhausted liquid. Check your codes you should get plenty and document all the information your reader gives you. You definitely have a bad catz and fuel problem maybe a faulty d sensor.