my 1997 tahoe will miss backing out of the garage, then it will clear up. When I leave for lunch it will miss, then clear up. Sometimes when I am driving pulling a grade it will really miss I will have it in cruise and keeps down shifting when it misses and then it will clear up. What could be going on?

 

I'd suspect fuel filter needs replaced

 

I had a motorhome with the 454. When those thongs started missing under load the common fix was new distributor cap, rotor button and wires.