help big time, fuel pump Options

[lime97celi]

my alternator + belt spark plugs and wires distributer cap and rotory but there was still a problem with my car ideling so i went on here for help and i was told to get my fuel injectors cleaned out. when i got it finished my car worked like brand new but i just recently went away on vacation with out me car for three days . i returned and started up my car it started up perfectly and was idling perfectly but heres the problem when eevr i put the pedal all thge way to the flooor it doesnt give me maxx horse power it only gives me a little the car still moves but not as fast as when i first fo the car its been happening for a very long time its lacking power big time. when i press on my gas pedal lightly its a very smooth ride its only when i speed i have loss of horse power. i thought it would be fuel related because i got my fuel injectors cleaned out last friday and after i got it done it didn't have that problem anymore. Is it the fuel pump? fuel Filter? idle air control motor? or does the timing just need to be adjusted? this problem has been driving me up a wall some one help me out please