Trying to troubleshoot with no fault code list. Truck has Woodward LPG mixer & regulator.
Was told plugs & coils were already replaced. Also some vacuum hoses to regulator.
Used pedal to retrieve faults 933 & 721.
Cleared faults.
Checked vacuum hoses & made sure orifices were clear.Removed map sensor (sensor in inlet manifold).
Don't know what 2 valves behind fuel regulator are or what functions they serve.
Check engine light came back on this time has a 751 fault.
Anyone know what I should look for next?