05 chevy trailblazer reduced power mode

Hello Joyce. First things first on the misfire.....Swap the coil from cylinder #6 (it's the last one, next to firewall) with # 5. See if the code changes to P0305. If so, get a new coil. for the MAF/MAP, you can try cleaning them first. The MAF is located on the corrigated hose that goes from the airbox/filter to the plastic resonator. 2 screws. The MAP is located to the right of the throttle body, stick up 90 degrees under where hood meets.

I already replaced the map sensor. This vehicle doesnt have a idle air control valve or a maf sensor.

I need to read your full story first! lol OK, 05 must be the last year without a stand alone MAF, the MAP is doing it's job. Next step, check your vaccum hoses for leaks. When you replaced the throttle body, did you re-use the hard rubber gasket too? Usuallly green in color with a small tab on the top. For cylinder #6, you did the coil trick already I see. We have a faulty hood seal that can allow water to get into the sparkplug holes on #4 5, and 6. Make sure no water in there, or excessive oil from a bad valve cover gasket. Other than that, you may have to check out that injector.

Just thinking a little more. You might have your intake smoked if you can't find something obvious on the idle problem. Or better yet, hook a shopvac up to a long extension cord away from vehicle, hook a garden hose up, and run it to your air intake. See if you can hear any sucking sounds. Problems I've seen here, are loose intake bolts, leaks between airbox and throttle body, and the problem child hose under the plastic resonator. That little curly hose under the resonator doesn't like to seat right, even a new hose. Put hose clamps on both sides.