running bad

[gmcjimmy90]

i have a 1990 gmc jimmy(fullsize) with a 350 700r and this morning when i was coming home from work it started missing got home and checked everything out all plugs are firing fuel filter recently changed, and no vaccum leaks that i could find. It sounds like a carb. loading up,but it is tbi. have checked and it doesnt look like it is dumping to much fuel.

 

[southernspeed]

How did you check your plugs? Just because a plug is firing when it's out of the engine doesn't mean it'll fire under cylinder pressure. Unless they're new I'd try a new set unless the misfire feels like more than one plug (it would be strange for several to go at once).
Have you checked for trouble codes?