Sister in law 2005 mdx looses power. I changed spark plugs, cleaned the egr valve/ ports/ intake .....ckeaned all the carbon out......etc...i even serviced most of her fluids such as coolant drain and refill, trans fluid change 3 steps change......I even cleaned all her tranny solenoids.......As u can tell this car had many issues due to poor maintenance.....I tackled the tranny first since it had hard shift..and fixed it....... When in park or neutral car revs fine even when pressing the pedal however on drive if i floor it, the car will start choking and the rpm and speedometer will start to decrease. I suspect a clogged catalytic but would think it would do the same when in park or neutral. When i remove O2 sensor 1 from bank 2 (air to fuel sensor) the car doesnt choke and drives normally except for and extremely loud noise. What can create this loss of power? Clogged catalytic? Valve agjustments? Vacuum leak?.....please help!