running like SH%T
 

I have no idea what i going on with my car now. She starts fine, idel's fine, and rev's up fine, well as long as she's not under load. If there is anyone out there that can help me this is what she is doin: when i take off its fine, but then after a minute or two of driving and i start reving her up she will all of a sudden start to chug and hesitate to rev any higher. Unless i put it to the floor then she rev's right up. Does anyone have any ideas? thanks for anyones help. oh ya and i have replaced the fuel filter and tryed all sorts of things with the fuel.

bad mass air sensor, or coil