[Jeff Higgins]

I have never seen this before. This was happening with one of my good buddy's cars, motivated by his X-Factory built 2.5, twin plugged short stroke. You know how a carbureted motor will bog if the throttle is opened very rapidly if the accelerator pumps are not squirting? They make that kind of hollow gasp, won't rev, and will even die altogether if you get too aggressive on the throttle? But if the throttle is opened more slowly, it revs just fine, with no indication of trouble. Well, I have never seen MFI behave that way, until this time.

We put our heads together and tried to come up with what might have been happening. It was as if the stylus was not tracking on the space cam. Like its linkage or something was gummed up. Slowly rotating the space cam when the throttles open, the stylus seemed to be tracking it just fine. Moving the space cam rapidly acted as if the stylus was left hovering above it for a split second, not keeping up, not providing enough fuel to let it rev.

What would cause such a thing? We eventually reasoned it had to be in the "fuel head" area, where the pistons, their sleeves, and the toothed rack reside. We thought it might be varnished up to the point that rack movement was hindered. So, on a hope and a prayer, he dumped a can of Seafoam into the gas tank and went for a drive. About 120 miles down the road, it cleared up. Runs like a champ now.

Anyone ever seen this before?