Had currently posted as F115 needs purging. I replaced all lines, clamps, priming bulb, and o-ring, because I had seen an air pocket in low side fuel filter bowl. After sitting overnight, will start fine, but will not go over 2,000 rpm's without stahling. I bleed the low and high presure fuel systems and the egine will run fine the rest of the day. I removed vapor separator tank as you had suggested and filter and bowl are spotless. I have purchased over $1,400.00 in parts from your company to overhaul the engine. All sensors are new, oil pump is new, and engine runs beautiful once I have purged the fuel systems.