iknow666

Hey all. 1989 Nissan 240sxSE with a KA24DE(twin cam) under the hood.
Symptoms:
-Shakes HARD when idling
-Sputters when accelerating
-Extreme loss of power and acceleration
-struggles and shakes to get up to speed but can get up to 100mph
-only shakes when idling and when pressing gas pedal
-shaking stops when in gear but not pressing gas pedal
-gas pedal sticks in morning at at night (cold weather?)
-gas pedal sticking started 1 week after shaking/struggling started
-car sounds like a motorcycle now! increased exhaust volume

Info about Car:
- 2 1/2" Straight piping exhaust (no catalytic converter)
-Engine/motor mounts/bushings/spark plugs and wires were replaced 11 months ago
-MAF replaced 4 months ago
-Fuel injectors recently replaced
-fuel pump replaced 6 months ago
-exhaust system specialty shop assures me my muffler is not clogged and exhaust appears to be fine

Any and all suggestions/inquiries are EXTREMELY appreciated.
Thank you