92 1.8 could timming belt be off 1 tooth

replace head gasket,did not take intake or exhaust manifold off. head was not cracked, just gasket on one end push out. head not warpped.all is fine but now the engine idle goes up and down to an almost stall. some times is ok.driving ther is no power until you get up to speed.almost like a plugged catalostic convertor. but when up to speed you stomp on the gas and it down shifts on goes good. i have books , i am pretty sure timing on belt is right with marks lined up. but could it be doing this if you are off 1 tooth

found problem ... the center shaft to distributor was a tooth off...must have moved when i installed belt and tensioner?? but is ok...