Altim 2006 2.5 - Poor Acceleration

@laminturay have the OBD scanned. It appears that your Altima has difficulty whenever under a load (where it has to work a bit harder) This could be a fuel problem as well as a combustion issue (poor compression etc.) as well as issues with the emission control. There are to many possibilities and we'll need a good starting point.

There are a few things that can be commonly causing this. You would need to check for a clogged air filter, worn spark plugs, dirty mass air flow sensor (MAF), dirty throttle body, clogged fuel filter, bad fuel pump, failed oxygen sensor, and even a clogged catalytic converter. Anything after that would be deeper inside your engine like blown head gasket, bad piston rings, leaking valves etc. As you can see the list can be pretty extensive.