smog?

I just recently bought a 1993 eagle talon dl 1.8 liters. I took it to get it smogged and the smog didn't pass. I changed the catalytic converter and I put a new exhaust. I took it again and it didn't pass again. I changed the fuel filter, the spark plugs, the oil,oil filter and it still didn't pass the smog. It passed everything except for one of the emission part. I was wondering if anyone knows what else I should check. I know that the heads and the engine is working fine. The car only has 138000 miles.
thanks
for any help