Ihave a gmc 1500 -2000 model seirra any way has a shutter or hesitation will not trigger check engine light does it mostly when you are starting up a hill and you barely mash gas then it does it breif?
Beginning signs of a weakening fuel pump. My 1997 did the same thing and eventually DID set the check engine light. Is your fuel pump getting noisey? I would be in overdrive and just press down a little to go up the hill and it would shudder, or if I was passing someone and just give it enough throttle to get by and try to go just a bit faster, you could feel it hesitate. You may want to change out your fuel filter soon to maybe buy some time on this. Believe it or not, on my 2000 2500 w/6liter, twice the plug wires were the cause, it was doing exactly how you described it!!