Check the exhaust system for restriction and also the EGR valve to include the fuel pressure

thanks :)

Check for up stream exhaust leaks.

why did you change it?

Hey there...we changed it cause it was running horribly..so we changed the spark plugs, fuel filter and it still ran like crap..when we removed the c.converter there was charcoal stuff falling out of it so i knew it was clogged..then we put the new one on which we bought new from advanced auto it ran perfectly for bout 35sec then i heard "POP" and then it kept making the popping noise and the converter was like kicking back too...the noise came from the converter...there was smoke coming from the exhaust pipe too....this has been such a head ach ...we tightened it up last night too but it still does the same thing..im going nuts here and cant afford to take it to the shop

sounds like it's still running badly not because of CAT though. no CEL on to get codes from to help diagnose?