car still wants to stall after changing sensors

I am sorry to say, you wasted your money. The P0420 and P0430 code refer to inefficient catalysts. Yes, it can be caused by an exhaust leak (rare) or faulty sensors (rare), but 95% of the time, it's the converters that are ineffective, most likely due to some kind of engine misfire historically and excessive passing through of fuel that has overheated them. Your catalysts, in fact, are probably clogged -- evident by your lack of power and stalling. The MAF sensor is entirely a guess that has zero to do with those codes. I'm sorry you are having this problem, and encourage you to seek guidance on replacing your catalytic converters...which unfortunately is a pricey proposition.

Check the kitty-cats. Probably an exhaust flow issue the catalytic converter.....