P0301, 2001 FORD ranger, how to fix

Question

replaced: 6 injectors, spark plugs and wires, intake plenum gasket, fuel filter, checked compresion

Answer 1

Hi there,

With all that you have done, I would do a leak down test. This will show things a compression test will miss. A very small amount of cylinder leakage due to a bad valve, maybe some carbon buildup so it's not sealing tight when the engine is running. A compression test misses that when a leak down will find that or a possible head gasket issue.