I took my fuel pump out today and there was a yellow box floating in tank what is it and do I have a problem 1989.

The yellow box was attached to the bottom of the fuel tank and the fuel pump intake rested in it.  The idea was that going around corners the fuel might slosh to the side, but that box would give you enough fuel to avoid momentary starvation. if it breaks loose its hard to re-attach.  People recommend cutting up a 1 quart oil jug and slipping it around the fuel pump. Google it, if you want to try it.  you need to cut some holes in the oil bottle so gas can get in, but not too many. 

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