2001 Volkswagen Jetta 2.0L with engine code P0170

Question

I have a problem with my 2001 Volkswagen Jetta 2.0L, I just clean the MAF. clean the air filter
and check the muffler and still the light on what can it be

Answer 1

P0170 Fuel trim malfunction Bank 1

Some of the cause for a P0170 that gets overlook are the crankcase ventilation system any leak there will cause a P0170 this includes the oil dipstick

 

A broken oil dipstick shaft will cause a P0170 as well as any leaks with the crankcase system