I have a 2001 Chevy Silverado 1500, 4.8 truck.

6 months ago my fuel pump died on me, I got a new one put in, and about a week ago, it died on me again. I took it back to the shop and they replaced the fuel pump (it was under warranty.)

After I picked the truck up, I noticed the truck was sputtering each time I accelerated and I could feel it missing when I was idling. I took it back to the shop and they said I need a tune up (which I did, it was about 55,000 miles since my last tune up) They changed the spark plugs and wires, and also put a new fuel filter on and also did an oil change.

I went back and got my truck and it drove great for the first day, then I noticed when I was idle, I felt it sputtering again. I didn't think anything of it, but then when I start slowly accelerating at 50-60MPH I feel it sputtering really bad. If I floor it at that speed, there is no sputtering, it only sputters when I'm slowing accelerating.

What do you think could be causing the sputtering? I'm in the process of cleaning my filthy air filter, in hopes that this could be the problem.

Also, my check engine light has been on for roughly 6 months - I'm not sure of the code, but I know it's the code that indicates a small leak in the evap system (already replaced gas cap and no luck)

Any help will be greatly appreciated!