05 chevy trailblazer reduced power mode

Asked by Joycearlene19 Apr 16, 2020 at 11:35 PM about the 2005 Chevrolet Trailblazer LS RWD

Question type: Maintenance & Repair

My husband's 2005 Chevy trailblazer revs to 4,000 rpms at
start and goes into reduced power mode. Check engine
light came on and said cylinder 6 needed a spark plug. We
bought it and it still did it so we bought the coil pack and it
still does it. Another code came up for MAP sensor so I
replaced that as well. It is still showing that cyclinder 6 is
misfiring. We then went to a junk yard and bought a throttle
body, still nothing. I'm at a complete loss and dont know
where else to turn. Can anyone please help?

4 Answers


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 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.

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