Oldsmobile running really rough!?

I have an 88 olds, eighty eight series with a 3800 engine and for the past week it has been running rougher and rougher, I have so far changed the air filter, pcv valve, fuel filter, a section of fuel return hose. A year ago I changed the crank sensor, good quality wires and plugs and a new coil. What else can it be? I have a haynes manual but it doesn't give me much on 3800 engines so I am running a little blind. I am very mechanicaly inclined but have little knowledge when it comes to cars ( eventhough I have basicaly repaired everything my self.) 1 more thing I noticed is that the cars behaviour doesn't change if the gas cap is removed, shouldn't it ! the ecm has not had any warning lights or codes either.Oldsmobile running really rough!?
i used to be certified master tech with gm. you could have several problems. try tapping lightly on the ecm (engine contro module) which is located below the glove compartment and see if the engine stumbles or changes rpm's. also check your pcv hose at the front of the engine, it is kind of hard to see. there has also been problems of vehicles running rough and losing coolant. have your engine pressure tested.Oldsmobile running really rough!?
i personally believe that it could be in need of a complete engine overhaul, especially if it has more than 100,000 miles on it and hasnt had an overhaul in less than 3 years. also no about the gas cap, if it is a 1988 then it shouldnt have any problem with the gas cap being off, my 85 monte carlo ss doesnt have any problem when i drove it without one, i believe that is with newer cars such as the mid 90's and up.Oldsmobile running really rough!?
this is an obd1 vehicle, it doesnt know if the gas cap is on or not. check the fuel filter, and fuel pump pressure. check the fuel pressure regulator for internal leakage. you may have a bad injector if all checks right.