Sluggish

Hi all, new here
Just wanted to get some other opinions.
I have a 2000 Accent 1.5CDX
My car has gone in for a repair, the garage told me they changet the Air regulator, reason was my car was very sluggish some times then would be fine (If I could describe it, it was like the car had a loss in power, you could put the accelerator full but this wouldn't help then all of a sudden it all comes right) so this would go on then off then on then off, this is very annoying as the Check light has come on and the same problem has occured and only a week since it went in.

Any help would be appreciated.

Sounds to me like a bad Throttle position sensor, that could cause the power flux and the light coming on.