Help Please!

[sexygomer]

ok, here's the deal, again, did a head gasket about a month ago, did the timing, checked the ignition timing with a light, got that good to go, did the cam timing three of four times before i got it right, and im 97% positive i have it right....but, when i gun it, it doesn't pull till about 4grand. i installed a a/f guage and at idle or even pedal the guage jumps from lean to rich. is it the timing or could a vacuum leak cause this also (my temp control doesnt switch from defrost) im just lost any help please thanx, and sorry for the length.

does it pull past 4 grand at half throttle?? A car will pull through the rpm range with cam timing pretty screwed up, ignition, however will kill you, how did you set this?? the heat thing makes it sound like vac, maybee affecting the map sensor?