car doesn't speed well especially when i use the ac on 2003 Honda Accord

my accord has trouble accelerating as it should, its a v6 and accelerates like a 4cyl. it feels like there's a drag. my local mechanic advised me to replace the fuel pump that its pressure might be low. i did that and there's no difference, i was also advised to service my nozzles, did the same, no improvement. please can some one help? its frustrating, i don't enjoy the car anymore.

Asked by for the 2003 Honda Accord
Check trans.
Thanks for your response. What are the symptoms of a defective transmission?
Could be transmission fluid level or filter partially clogged if that's not it could also be alternatorbeen check output on alternator just because of runs worse with a/c on let me know if I helped you
1 more answer , 1 more comment
Before changing the fuel pump, you should check the fuel pressure. I suggest you to have somebody perform a complete diagnostics. If it feels like dragging it may be a caliper, brakes. However it is hard to say based on what you have described. I need more info, like when do you feel dragging, etc.
Thank you so much for you response, the car seems to move freely when the ac is off but as soon as i turn it on, the acceleration almost immediately drops, it struggles to reach top speed. it doesnt give good bursts of speed when i push down the tottle/accelerator . its a v6, it used to be a joy to push down the tottle and hear it "roar" and take off, i dont get that anymore. i tend not to use my air conditioner, only if its extremely hot. I have also noticed it wont go passed 100kph. bottom line, it now drives like a 4cl engine. the gear selects reasonably well bt sometimes its not as smooth wen shifting. i love the car but looks like i might have to sell..