87 Burb Tbi sputtering problem

[Kapote]

Ok guys I am new to the TBI world. I bought a 87 last year and so far its been fine, however yesterday I was up in the mountains, where it performed fine. But when I got back in the city I took off from a stop light and it sputtered in the mid-range, not like fall on its face but you could hear the exhaust stuttering. When i got home i popped the hood and the passenger side exhaust on the back side almost looked like it was slightly glowing red... I drove it today and it only seems to do it when warmed up and pulling off a 55MPH road onto a 35... then it sputters mid throttle..

Any ideas??