I have a 02 Silverado 5.3L Z71 its been raining here a lot the past week I drove my truck and it was running fine and all of a sudden its starts sputtering and loseing power while I'am driven.I change the fuel filter,plugs and wires got it check at the auto parts store for any codes that might show something.Well all the codes came out OK didn't show nothing that would do that to the truck.After I change my plugs it started acting a little better but it will run good when I start it and about 2 blocks down the road it starts to sputter when I go to take off and when the speed gets up a little it runs good.does anyone have any suggestion before I have to take it to the shop and spend more then I have.Thank you for any info.

Well all the codes came out OK didn't show nothing that would do that to the truck.

What exact codes were thrown?

Did you install the same ACDelco spark plugs that came in the truck?

Check/replace the Mass Air Flow (MAF) Sensor and seal.

Check/replace the Engine Coolant Temperature (ECT) Sensor.

My bet is it's a bad MAF Sensor--easy to replace. BWD sells MAF Sensors with a lifetime warranty (Advance Auto Parts).