PO301 Fault Code on 1999 Ford Taurus 3.0L Engine: Diagnosis and Solutions
I own a 1999 Ford Taurus with a 3.0L engine and have been consistently encountering the PO301 diagnostic trouble code. I've already replaced the spark plugs, plug wires, coil pack, and had the fuel injectors professionally cleaned. The engine runs roughly at idle but smooths out around 1500 RPM. Notably, the PO301 code does not appear immediately—it sometimes takes several days of driving before it shows up. The engine does not miss under load. Despite these efforts, the issue persists. What could be causing this? Are there any other diagnostic steps or component checks I should consider?
Could you specify the brand of replacement parts used? Try swapping fuel injectors #1 and #2, clear the code, then drive the vehicle to see if the PO301 code shifts to a different cylinder. Also, how many miles does your vehicle have on the odometer? What did the old spark plugs look like before replacement?