EPC light and check engine light ON and loses power (2001 VW Beetle)

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Hi- I have a 2001 vw beetle. Right after I had it inspected (NJ) the epc light comes on and the check engine light too and loses power once in awhile (which I have to turned it off and on again and would be fine for a couple of miles and loses power again) I've read a lot about it, and most of the people said its the throttle body, so I had it replaced (2nd hand oem throttle body) it was actually fine after 300miles on it, the light is on again. Grrrrr!!!! I also know that there was a recall for this beetle about the brake light switch, so I went to the VW dealership, and they replaced it for free. But as I expected, I think my beetle is in the worst condition now. Both lights are still on. And I can't use it anymore. My mechanic said they had to check the computer of the car and it will take time and money. And the sad part was my mechanic can't give me an estimate on how much I would be paying. So I am desperate to have my beetle fix. Hope someone can help me. Thanks!