wont maintain speed after hard acceleration

97 2.2l - usually happens after hard acceleration onto hwy, bogs and bucks, punch it and it speeds up fine but wont maintain once you reach speed. this doesnt happen after slow acceleration to same speeds or w/ o2 sensor disconnected. ive had 2 mechanics go over this and the closest they could come was its probably the fuel pump or possibly injectors. but only after hard accel? (i was thinking more like a air/fuel sensor or computer problem)i surely dont want to start replacing expensive parts without defing the cause. tune-up and fuel filter done. codes say lean, lean. thanx for any help or guideance:banghead:

look at ur car and on the engine like the front drivers side corner and if u look u can see a blue square sensor disconnect this and take it for a drive if taht does fix it then its the senosr. this sensor controls the overdrive. wut type of speeds are u driving? does the speed go down slow?

its like a misfire,running,but missing and losing speed. it can happen as slow as 35mph after hard accel. hit the gas and downshift and takes off great, level speed and misfires start. going to check blue sensor 2nite. ty