car shakes under acceleration

2000 grand prix gtp. I posted this question a few times a while back in the grand pix section and wasnt able to resolve the issue, being is how its not really a make/model relevent problem i figured i'd try asking here. while driving the car shakes when im on the throttle, but not while coasting. feels like a wheel hub is loose. i have taken it to at least 5 mechanics including dealerships and all say its something different, and after doing work the problem remains. the shake is worse the faster im moving, but isnt effected by how much gas i give it. i have had wheels balenced, wheel hubs, speed sensors, tires and brakes replaced. computer scan only codes evap small leak, which I cant see being in any way related. I just got my car out of another shop for brakes and tires, they checked the front end suspention mounts etc and was told everything looks good. I am at a complete loss as to what this could be or what to do.at this point its been an issue for 3 years. somebody please help! any info advice or ideas would be greatly appreciated.

have you replaced your cv axles i have seen this many times on fwd cars if the axle is warped it wil twist under load causing more distortion to check this raise the car on a lift while in gear and front tires spinning if the axle apears to warped replace it or both if needed hope this helps

Have suspension and tires looked at at local tire store. Whatever your problem is, it can be diagnosed for free here. . Might be a suspension bushing. THey can tell you, give you an estimate, and then you can shop for best repair price. Good luck!!