Any recommendations as to what plugs and plug wires to buy?

seems to be an ongoing debate. you need at least platinum on that engine to make it run good. wires are tough i used to buy nothing but delphi or delco but now they seem as bad as the cheap Chinese ones. i bought the middle range autozone ones a couple times with pretty good luck.

I used NGK Platinum plugs & Wires. 2 years later, both are still in excellent shape.
The NGK are exact fit to vehicle/engine required lengths as well.

Well I changed the spark plugs and wires...didn't help. I've been researching online and some possibilities are a fuel issue (filter, pump, etc.) or bad ignition coil packs. I changed the fuel filter (didn't help) but I'm sure it needed it anyway. I'll probably just take it in again and hope it acts up for the mechanic.

try testing tps

https://www.gmforum.com/trouble-shoo...sensor-279319/

I've read that could be a possibility too. Good idea! Looks like an easy test. I will do that for sure