91 Caravan starts, then loses power

Replaced the fuel pump 4 days ago and it ran like new for 2 days. Then, on the highway, it started losing power...pops or backfires when accelerator depressed.
If left to sit for 5 minutes, it starts up and runs fine for 1/4 mile, then will only run at idle speed...Checked fuel flow, FPR, ASR, VSS, hoses and wires, replaced inline filter, tried injector cleaner and fuel line deicer...no change.

Not an expert. Few of us are. Here's my thought. It's not unheard of for new pumps to be bad, especially non-oem pumps. I would suggest you find a way to get a fuel pressure gauge connected when the car is not running well. It should reveal or eliminate a bad pump.

Thanks for the reply!!! Any advice is MUCH appreciated! I'll see if I can find someone with a pressure guage to do the testing.