Awhile back, I had my engine rebuilt. Ever since, my throttle sit at about .6 and feels like it's about to stall. I disassemble the whole throttle body and cleaned the crap out of the valve and everything else. It ran smoothly for about a week (about .75) and now it's back it .6 again. Did it get dirty in that time? Something seems wrong, obviously.. can it be anything else other than the throttle body?