I have a 1982 trans am 305 . when we got it we think it sat for a long time and didn't run. we ran it for a few days and it was great but turned out it was out of gas. really out of gas. filled it up and then it didn't want to run anymore. chugged really bad. replaced fuel pump and it sat for a few months. turned out the new pump had a spring break so it didn't have pressure. put another fuel pump on and it ran great. we just drove it down the road a few times. the next day we put a cat. on it because the old one blew and it wouldn't run again. it will idle great and sounds good but when you try to go or hit the gas it acts like it doesn't have any gas. it chugs really bad stumbles and dies. every time but it idles great. i took the fuel line off the carb and cranked the engine and lots of chunks of black stuff came out with the gas. could the tank be clogged? it never has pressure when you take the gas cap off. also, when the cat was on it gave code 13 but with it off no code. PLEASE HELP????