Timing seems to be correct, CEL giving O2 sensor problem. Changed the O2 sensor, no change. Changed MAP sensor, no change. When accelerating, the car has lag. Like it's going to kill or backfire if you hold it. Problem occured after pulling engine to replace timing belt, water pump, auto tensioner and misc pulleys. Any suggestions?

 

A bad O2 sensor indicates a problem with your A/F ratio.

Check your fuel system. You most likly damaged something during the pull.

 

inspect timing

make sure the map sensor is getting vacuum.

 

Yep, double and triple check your timing with the flywheel marks and cam gears.

 

I'll recheck things. Hopefully it's one of the things mentioned.