Flex Fuel Fuel Pump 2002 Chevy S10

[taw50xx]

I had a mechanic to install a fuel pump in my 2002 s10 2.2 4 cyl. Neither he nor I realized was flex fuel. I supplied pump and fuel filter from NAPA. He and another guy did it one night. He told me filter was wrong and he put old filter back in.

Truck ran great for 3 days and next morning ran very rough and has every since. He claimed he did cyl. check and 1 cyl no compression. He thought probably dropped a valve and not worth fixing ( 205,000 mi ) I wonder if old fuel filter got clogged up. I would try another filter but they are like 60.00 for flex filter, plus labor. Any advice appreciated.