1995 Mazda 626 2.0 auto

Car left in the yard for 3 yrs son bought it and drove it part way home it died, I got it home and started it, it ran smooth, checked the water it was out added water to radiator and found the head gasket was blown, replaced head gasket and water pump, first time we started the car the timing was off with the cams and all remidied this and it and drove the car up the street and back ( 1/2) mile or so, but now the car starts, but will not acclerate at all, it sounds like its bogging down and shudders, still it will return to idle and run ok, the codes from the check engine light said " mas air flow sensor" and throttle position sensor", which one is the culprit, or is there something else that might be the problem? Really could use some help on this one. "Dad is supposed to fix everything you know "