Replaced Fuel Pump... Lost MPG

1997 GMC Yukon 5.7 engine 92,000 miles I just had the fuel pump replaced and for some reason my gas mileage dropped from 18.8 to 16.8 highway driving.
I drive the same 400 mile route often and am at a loss as to why the drop in MPG. The only change was the fuel pump. Coincidence? or not? TIA JR
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You replacd your fuel pump and your MPG went down? Did you check for a leak in the line? how about an injector malfunction now that the fuel pressure increased? Are you sure there isn't a leak at the tank where the pump mounts to it?
Or, here's one we pulled on a guy who was bragging about is car's gas mileage. Every night, we'd dump some gas into his car's gas tank and his mileage went through the roof (he was elated). Then, we started siphoning gas out every day and everything went bust. Moral - Make sure your friends aren't screwin' with you.
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The pump was replaced by a speed shop. I can't smell any leaking gas. two round trips of 400 miles with the same 16.8 mpg The last trip was with the AC off due to Hurricane Ivan passing thru. The previous dozen trips were at 18.8 mpg. The only diff is the new pump. It's not throwing any codes. Could a lean run condition just b4 the pump failed cook the O2 sensors? JR
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Crap from the pump replacement in the fuel filter? Been known to happen.
RJ in WV

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I asked them to change the filter. Guess should crawl under there and take a look.
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