Timing woes Options

[90GSX]

Well i got my car back together, with the new head on it, and it ran really good. I drove it 60 miles and now my cams are about one tooth off on TDC. The belt still feels tight, and the tensioner is holding the tensioner arm within the specs. I replaced the idler pully, tensioner pully, and its a new tensionser (except ive been contunually recompressing it about 10 different times). When we set the cam gears by turning each one towards each other with a wrench, they actually stayed there without the belt on it. So i dont know where to begin trying to figure out how it managed to slip a tooth in timing. I did the belt using the VFAQ site, and im positive i did it correctly this time. Can you only compress the tensioner a few times and then its no good? or am i looking in the wrong spot for my answers? Im sure my valves are fine, as its only off by a tooth, so i guess i lucked out on that. I know i had it set right at first, cause i drove to to work and whatnot, and it was smooth, quiet and had power, i went out to start it, it sounded like an exhaust leak, and had no power at all and the engine was idling rough. Anyone know what i did wrong this time??