I have an '86 Berlinetta with the 2.8L. I've had it for about 10 years and oddly this problem is getting to really bug me about now. After I fill it up with gas, where the pump stops by itself and I do not pump anymore, and I drive off it then shuts off on me after I slow down. If I stop fast it acts funny then shuts off before I get to the light. I was told the fumes from the gas rush into the charcoal box which causes the engine to choke. I have quite a bit of knowledge of the engine but I know very little about the vacuum system and its components. What do I need to replace/clean/etc.? I'd appreciate your help guys.

 

Maybe your tank is not venting properly. There is a round canister with a replaceable charcoal filter in it next to your air filter can. Your tank vents through that. There is a solenoid on it.you could try unplugging it next fill up. Its some thing to look at.