I have a Walbro 392 and have been having trouble off and on with erratic fuel pressure lately. I changed the fuel filter and went for a test drive. At first it was fine and after about 3 miles I lost pressure and it died. The lift pump will not cycle at all now. Help.

 

it seems like your LP gave up

 

ULSD has not been kind to the Walbro setups.

 

Mine started acting up with fluctuating pressure for a couple weeks. I didn't mess around too long and replaced it with a Raptor. Left the Walbro right next to the Raptor as a backup, just in case.

 

Have you checked the Walbro Pre-Filter to make sure it's not totally clogged?

 

I just changed the pre filter about 500 mile ago. I will change it when I install the new one. I put my volt meter on it then bumped the ignition to cycle the pump. I had voltage but no pump action. I ordered one from E-bay yesterday AM and it came today so when it warms up I will install the new one. Wish me luck.

 

I replaced my Walbro pump with a new one and my truck works fine. I opened up the old one and one brush was bad and gone. Hope this is not a common problem. The old one is about 2 years old.