I HAVE REPLACED everything listed for the CEL codes:
P0171 and P0440 always together.
1997 VW Golf, 4 cyl. OBD II
New MAS New front heated Oxy sensor All new vacuum hoses, including brake booster hose New spark plugs New Ignition wires New cap and rotor new fuel filter New air filter New PVC system Cleaned fuel injection system, including injectors New gas tank cap All new intake gaskets and seals New fuel pressure regulator New exhaust Cleaned and aligned throtte body
Reset CELs many times
P0171 Fuel trim too lean
P0440 Evaporative emission control system malfunction
A vacuum leak at the Evaporative purge hose can cause this code condition ,
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