I have a 1984 Z28. This past summer I put lot's of new parts into this car, the least of which was a new fuel tank and sending unit. If it matters, the tank came from Autozone and the sending unit (w/an electric pump) came from O'Reilly's. These parts are technically for a 1985 model becasue the 82 - 84 parts are not available locally otherwise (dealer shows them as "discontinued").

Anyway, everything works fine until about 1/4 tank left, approx. 3 - 4 gallons. At this point, the car acts as if it's running out of gas. I have pulled off one of the fuel lines from the motor mounted pump, and it truly appears the car is about out of gas. The flow is very low and not responsive. I know the tank holds 15 gallons and I only need to put in 11 - 12 gallons whenever I've filled it. As you all know, the tank is right above the damn muffler. This, too, is new as is the entire exhaust system and I'm not happy about cutting it out to drop the tank.

So, I have a couple questions:

1) Why did the carburetor only years (82 - 84) need a tank mounted electric pump AND a block mounted mechanical pump? Is the mechanical pump closer to the ground, thus creating a flow vs. gravity issue?

2) Is there a better place to get a sending unit other than a place like O'Reilly's, in case I need to try another one?

3) Any other ideas before I have to cut something out?

Thanks in advance for any help offered.