Welcome to Justanswer ! my name is XXXXX XXXXX i will do my best to assist you with this problem
do you have any access to a scan tool to view live computer data ?
when it looses power does it bog down when you try to accelerate ?
I scan tool and yes when you give it gas bog down.
I also changed the mass air flow
I really don't know.
I did not have a scan tool with me.
ok we need to see if BOTH O2's are fixed below500MV when its acting up
if they are that is showing lean and since the MAF is new you more than likely have a plugged fuel filter or low fuel pressure causing this problem
since its bogging down usually leads to a MAF, plugged cat convertor, plugged fuel filter or low fuel pressure
you can also connect a fuel pressure gauge to the test port on the fuel rail and see if the fuel pressure is reading 55-62 psi key on engine off and hold
if its below that spec the fuel filter is plugged or you have a bad fuel pump
if you had a fuel pressure regulator issue it would cause very extended cranking problems
since you did not mention that as a problem its more than likely one of the 2 Dennis
they are 2 cat on truck would they both my bad.
very rare they both would go bad
and usually would not run good then choke out
usually when cats are plugged they act up all the time
ok thank you