Xray,


The problem is an error in mixture. Because engine operation at lean conditions can destroy the exhaust valves, it is favorable to correct the problem promptly. Fuel delivery could be compromised by incorrect fuel pressure, injector faults, etc. You also need to check that the correct input variables are being delivered to the fuel computer. For example, an air leak in the intake manifold path will skew the mixture lean.

Because an engine requires more fuel when cold, because of increased friction, it must have a richer mixture when starting. This is why lean mixtures display exaggerated symptoms when starting and shortly after. The choke is off.

Lack of rest fuel pressure caused by a defective check valve cannot exhibit symptoms for more then a few moments, because the fuel supply line contents is emptied quickly back into the tank via the return line path. A defective check valve could block the fuel flow, but would be easily diagnosed by incorrect fuel pressure. I seriously doubt that the fuel check valve is faulty, but you are welcome to change it anyway. They aren’t that expensive.


Lucid, There should be a positive rest pressure in the fuel line for a time to prevent hot soak vapor pockets that cause a difficult warm start. My rest fuel pressure usually is gone within a couple of hours.


Goatman