Air pump introducing false air?

[RobertISaar]

i've seen jammed/stuck/melted select/check valves cause some really goofy things to happen when AIR is involved, it really wouldn't surprise me if this were happening.

[1project2many]

Many years ago while I was just beginning to learn about computerized engine controls, I lost an engine to just this problem. The old CCC carburetor systems were very simple and a faulty diverter valve caused excess fuel to wash the cylinder walls and kill it. I also lost a couple of mufflers due to backfiring during downshifts.