gimmick

well i got a problem, this is where it all began /.i was driving home and then my car would feel like it was dying and it was dropping in rpms. i thought it was cuz my tps wasnt calibrated right cuz i just replaced my tps with a blox tps cuz it went out. i get the voltmeter and set it right but it still did that. i mean the car still had the power i just had to turn off the car then back on. then two days later when i was going to work the car would jerk and jump rpms. then when i got to a stop light the car turnedd off. i started it back up with ease no problems starting the car. so i changed my plugs,oil,filters, and seafoamed the motor.. after that the car ran great and fast so i know its not my internals in the motor cuz it ran faster than ever. then out of no where like 1 week later it starts again. car would idle low and almost die so i step on the gas to wake it up. then it would drive normal. then today i was going to work and it drove normally then i put it in 5th gear and it starts sputtering and going slow..but it drove fine in other gears. then i park the car goto work got off then started the car. and it was sputtering in all gears. when i step on the gas it feels like i am using the turbo button on my controller and trying to accelerate. and now the cap sputters at idle and all. what could it be?