Feels like I am dragging a trailor

[longms]

There are random times lately that my car will feel like it is straining to accelerate. Almost like there is a parachute behind me at times not allowing the car to accelerate. There are also times that the car feels fine and has very healthy acceleration. Car has roughly 254,xxx miles. Engine rebuild has about 10,000 miles. I have to replace Crank position sensor due to oil fouling it up and have not checked that yet (that was a different feeling than this though).

Mods:
Mark D 91 chip (always run 93)
AFE conical intake (maybe this needs cleaned???)
1 year old fuel filter
Bavauto coils and spark wires (need to go COP!!!)
4 pintle 19# injectors
Fuel pump was new 4 years ago (check the filter diaphragm???)

Thanks for any info guys and gals.

[mr ilia]

Does the engine sound healthy when "dragging the trailer"? If so, I'd look somewhere else.
You might have issue with parking brake shoes, where they get stuck and slow you down.

[longms]

Parking brakes haven't worked for tears. Also, when the car goes back to normal it feels like I am pulling with a rope and the rope suddenly brakes.

I will check the parking brake just to be sure.

[willworkfore30s]

Afm