Why are my exhaust glowing Cherry red

I bet it was the Catalytic Converter. Either you have a misfire or your engine is running rough and causing the cat to get red or it could be a clogged catalytic converter.

Just put new after market cats on. No check engine light?

So something else is going on that's killing the catalytic converters. A glowing converter usually means you have a misfiring engine that is dumping raw fuel into the catalytic converter. You'll need to have the engine trouble fixed then replace the catalytic converters again. Hope that helps! Jim

A glowing convertor at idle is an overheated soon to be damaged convertor. It is possible that you may have a leaking fuel injector or other issue.

Maybe other issue. Change the fuel injectors with motor craft my man new air cleaner assembly with the MAF sensor.

But i only change one coil since i had the car and all new spark plugs.

You only changed one coil? Maybe that is the problem. Have a muffler shop do a back pressure test on the cats.