car started lugging down when i accl.and then would not get over 60 mph.

What is your question?

1 mechanic changed o2 sensors.1 changed crankshaft sensor.1 changed some air flow sensor and cleand throttle body.my brother and i removed the fuelpump and cleand alot of gunk that looked like clay off of the little screen on the pump.I then put fuel system treatment and it ran great for about 2 dys and then back to running like crap.I really like this car and was going to give it to my son for highschool.can someone please tell me what the heck is wrong with this thing?oh and now when i am going down the road it will accellerate and slowdown constantly.