Timing Belt Replacement Causing P0171 System Too Rich Code in [Vehicle Model]?
I recently had my timing belt replaced on a [Vehicle Model]. Since then, the vehicle has been idling roughly and the check engine light is triggered with code P0171 — system too rich, Bank 1. The car ran smoothly before the timing belt replacement. I've already performed an oil change with a new filter and replaced the spark plugs. Could the timing belt installation have caused this issue? Any insight into whether the timing belt work might be responsible for the fuel mixture imbalance?
A diagnostic scan is recommended — check both stored codes and live data, including ECT (engine coolant temperature), manifold pressure, O2 sensor voltages, and cam/crank position correlation to identify if there's a sensor or timing issue contributing to the rich mixture.