power loss.. 3800 v-6 1989 Riviera

my rebuilt engine has 70k miles on it.. my stock parts have been transferred to the rebuilt engine too. when i take it for a drive, it
seems to be missing; engine will idle but run rough. feels like it chuggles along in drive; misses. transmission shifts welll, it goes
into all gears fine. i replaced MAF. i inspected all spark plugs, #2 has oil in the cylinder; rings getting shot in that one. NO
TROUBLE codes in the diagnostic mode. all cylinders seem to fire fine; all spark plugs fire. i have some gas smell on cold start ups.
22 year old ignition coil; never been changed same with catalytic converter. exhaust seems to flow freely. this started after
fueling up and going onto the highway.   we are the first and only owners of the car and have full service history. rest of car has
189k miles. i'm getting stumped.. should i go drop the fuel pump next??