I have 1979 z28. Not sure how long it was sitting before I bought it. But it drove fine for the first 4 months. Then It started have a hesitation and then would eventually die. I thought it was a vapor lock issue since it was in mid-summer. I changed out and insulated the fuel line from the fuel pump to the carb. This seemed to help for a few weeks. Then it got worse. It wasn't getting any fuel to the carb, so I replaced the fuel pump. And that fixed it for two days. Then I thought it might be a carb problem, thinking the float was getting stuck, so I re-built the carb. It didn't fix it. I am starting to wonder about the gas tank itself. Is there a way to find out if the tank has something in it that plugs the pump? I have this problem with a full tank or not. The books I have don't show a diagram on how the gas is drawn out of the tank.

 

First you check the fuel tank's cap some times it may cause vapour lock also, if it is ok, then there should be a hairy crack or leakage in the fuel pipe line. There may also a problem in fuel filter chock up. So go threw all these once.

 

if its carb then there should be a screen were the fuel line goes into the carb. check it. u could have a pluged fuel pickup in the tank or the float in the carb could be sticking. how old is the carb.

 

Better you find this answer from the service provider or on several related websites.

 

i had a similar problem before and i found out that i had a faulty fuel tank cap causing vapor lock and fuel spillage.. If its still not the problem, i advice you to let your mechanic check, it could be a lot of things.