My 2004 Jetta TDI has no power when going up hills; does fine when on flat land?
Any engine codes? A lot of factors can cause this. Fuel delivery problem, clogged CAT, etc...go to any Autozone and get a code scan done.
Was the loss in power sudden? Or has it gradually gotten worse over time? Make sure the transmission is downshifting appropriately. If not, it could be the TPS (throttle position sensor) or an issue with the transmission itself.
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