Originally Posted by tsmysak1

Too much unburnt fuel in the exhaust will cause this issue exactly. It can be a stuck injector and it can also be a bad injector o-ring. I take it the downpipe was probably glowing too. if you can see it clearly in normal daylight, then there is a problem. The exhaust is very hot and will eventually fatigue if left un-fixed. Check your gas mileage after normal driving. I would say if it is below 18 mpg with no boosting, then you have a fueling issue.

Also ditch the pre-cat if it is still installed. That is somewhat easy to take off... somewhat....well maybe not...