Looking for wisdom. I put a GT40P motor in my 84 LX convertible a few years back. It has always run great but recently it has become hard to start when cold and “coughs” under hard acceleration. Timing is dead on and the vacuum advance is working correctly. It has an Edelbrock 600 cfm 4bbl carb which I’m beginning to suspect is the problem but I really don’t know where to start on a diagnosis. Any thoughts would be welcomed.

 

Accelerator pump in the carb bad?

 

Bingo! Thank you.

 

Glad it was simple. My '65 Corvair has 4 single barrel carbs, so I have had my share of fun getting all working as they should.