runs like crap sometimes ??

hi all, i have a 96 olds cutlass with a 3.1 v6 with 105,000 miles on it. i am experiencing running problems with it now. i took it for the first little road trip a couple month back. i was running 80 to 90 miles an hour for 70 miles then had to slow to turn on to a different road and it started bucking and hesitating and sounded like a lifter started chattering. could have been a injector i dont know. it run like this for the next 25 miles to my destination. i went to the nearest gas station and put injector cleaner in it and it eventually came out of it. on the way home i was running 75mph with no problems till i got about 10 miles out and it started running like crap again. i started it the next day and it ran fine. it has acted up a few times since and came right out of it till i took another little trip. 60 miles up and 60 miles back with no probs till i went to pull onto my street and again bucking hesitating and chattering. start it in the morn now and almost always chatters. sometimes it comes out of it on its own going down the road other times if i turn it off and restart after a few minutes it will run just fine. i am leaning towards a fuel related or electrical problem but cant tie that in with the chattering that i am hearing. fuel pump cause this ?? low fuel pressure cause the injectors to chatter ?? would bad lifters rattle then stop just by turning off and restarting the engine ?? any sugestions would be greatly appreciated.
thanks
ron

Welcome to AF, some has to listen to this " chatter" on site to detemine the source, then we would have some idea of what to recommend. I assume the oil is full and clean, not overfilled.

Welcome to AF, some has to listen to this " chatter" on site to detemine the source, then we would have some idea of what to recommend. I assume the oil is full and clean, not overfilled.
oil is full and not over filled. i take my stethescope and place it on the valve cover and hear nothing when its acting up and when i place it on the front injectors i hear a loud tapping noise. have been told that i could be hearing lifter noise radiating up through the injectors. if it was lifters would they be acting like they was operated by a light switch. switch on rattle, switch off no more rattle ?? seems like thats how its going. check engine light never comes on. dont know if it has one. never see it even on start ups. is there anything fuel related that could cause this ?? rattle and run like crap ??
thanks
ron

See my post from a different reply concerning stalling. This stalling problem also sometimes created this "limp" mode of running, which my car went into sometimes, when IMO the MAC was stuck in the deceleration mode and it was starving the engine, resulting in the engine really laboring in order to move above 30 mph. Once it was stuck in this "deceleration" mode, it can often keep stalling upon restart. After resting, the problem seemed to go away probably after MAC sensor slowly unsticks. This may be related to running poorly.