96 toy camry

i have this 96 camry that i replace head gasket install cam gears by folowing a haynes repair manual to me everything is on point after double checking it three times. But the engine runs like the timing is off, hard to start, when it does it runs ruff with a miss at tail pipe> when i step on gas pedal it backfires in the intake with very poor acceleration 4000 rpm is the max . Please help me find something else if not timing

Look through these instructions and see if anything looks different or is described differently.

http://www.automotiveforums.com/vbulletin/showpost.php?p=3196113&postcount=5

If not, you better have someone else look at it with fresh eyes. I think you're missing something in the valve timing.