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This car is 88 civic. Fuel Inj. The motor runs great as long as I keep the fuel tank full. It will start to lope or surge & lose power when I reach @ 3/4 tank, I'm not kidding. I've tried fuel inj. cleaners, octain boosters, high test gas & fuel filters. once I fill up - it runs great. I wonder about the fuel pump, but would the level of fuel in the tank affect this?

 
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Sounds like a fuel pump...

It sounds like you changed the fuel filter right?

My next guess would be the fuel pump because it probably is not covered when the tank hits 3/4 full, so it's probably a seal in the fuel pump. And the classic surge and die is that of a fuel pump about to die.

 
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I'd go with the fuel pump too.

 
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Thx for your insight. The fuel pump is what I was thinking, but not certain.

 
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Thx - The pump is what I was thinking.

 
Rep Power: 302

Oh.... one quick test....

Next time it surges, pull over, leave the engine running and pull the gascap. If you hear a strong suction sound, you have a plugged vapor return putting too much vaccum into the tank. This will give your fuel pump a lot of trouble.

If nothing happens.... then change the pump.

 
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Thx Tinman