Well I have been having this problem for a while now with the Silver 2000 Tiburon automatic. It started one day when I was traveling up a large steep hill to get to work. It bogged down (loss of power) slightly and I could barely feel it. A few days later it almost dies complete going up the same hill. I'll start up the hill around 50mph and hold my throttle about 3/4 of the way and it'll die like the power was cut (all eactrical works fine). It'll coast down through the gearsuntil it's almost stopped, then suddenly, wham, full bore ahead. At this time it is only doing it on this incline. It is the only big hill around my house. About a week later it is doing this all the time even on flat straights. The car was impossible to drive. I took it to my dad's shop and used a scanner, hoever no codes are getting triggered. The was a lot of people getting bad fuel from the station I was fueling at, so my dad told me to change the filter. I changed the fuel filter (and full tune-up) with a premium Puralator fuel filter from Advaced Auto Parts (and cleaned the MAF) and the car ran like new again. This only lasted for about a week and I felt the slight stumble going up the hill again. Couple days later I barely make it up the hill. Couple days after that and it barely runs at all again. I buy another fuel filter from Advance. Runs awesome, however the cycle starts all over again! I am on my fourth filter now...
Another interesting note is while it would bog at 1-99% throttle at 100% WOT the car always ran great. When it would bog down if I would shove the pedal into the engine bay it would take off. This made me think my throttle position sensor could be off a bit or something.

There are no codes being triggered.

I thought maybe there were deposits in my fuel tank, a failing fuel pump, or a faulty coil.

Deposits in my fuel tank would be my best guess as why else would it run great after I change the fuel filter.
Only thing is why can I drive the car hard around sharp bumpy curves and such for extended periods of time
after I change the filter. Surely the fuel gets sloshed around & stirred up a lot more. It'll run great few a afterwards and then the cycle will start again.

Just wondering if anyone else has had this issue or know of another item I should check.

 

I've never been able to get my car to 100% throttle. It always maxes at 90% according to my OBD. Maybe you have an issue with your TPS sensor.

I'd suggest getting some OBD tools and checking your sensors out.

 

I have had it on our Matco 'Determinator' scan tool lots...lol too much! I have even drove a few days with it plugged in so I can watch everything work/function...

 

Did you change fuels?

If it keeps clogging your filter, drop your fuel tank and have a look inside.