How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Bill Your Own Question
Bill, Chevy Technician
Category: Chevy
Satisfied Customers: 1776
Experience:  GM Certified Master Technician
Type Your Chevy Question Here...
Bill is online now
A new question is answered every 9 seconds

Chevrolet Trailblazer My 2002 trailblazer runs rough until

Resolved Question:

My 2002 trailblazer runs rough until it warms up. This just happen during this summertime. Had all plugs changed and the heat sensor replaced as it show -44 degrees. I did notice thee engine light flicker, but it doesn't seem to be doing it now?
Submitted: 6 years ago.
Category: Chevy
Expert:  Bill replied 6 years ago.

Welcome to Just I'm here to help you and your 100% satisfaction is my goal. Please Accept if you are satisfied.


Have you had the vehicle scanned for fault codes and also does it feel like a misfire while driving or more like a vibration at idle and low speeds or when putting the vehicle in drive or reverse?

Customer: replied 6 years ago.
Apparently my mechanic said there were no fault codes. It appears to be a miss fire as the RPMs go down and loses power and when I try to add more fuel (gas Pedal) it will either misfire of stall. I will start up right away. When I first start it in the morning and wait for the engine to warm up in the area of 180 to 200 degrees then I can drive away with no problems. It will tend to vibrate but runs rough and that will make it vibrate in a sense
Expert:  Bill replied 6 years ago.

Remove the air intake where it meets the throttle body and clean out the area where the butterfly is. There is likely carbon build up in there. These are notorious for two things. Oxygen sensors causing stalls and lean conditions while setting no fault codes and your vibration is almost definately going to be caused by motor mounts. The oxygen sensor is not used during the initial warm up but after several moments. That is when the vehicle goes into closed loop mode and adjusts the fuel mixture based on the o2 sensor. If this reading is slewed, it will cause a lean or rich condition. The mounts are hydraulic and sag over time. When the mounts are removed you will likely find them 1/2 to 3/4 inch shorter than the new ones. This will cause a vibration at idle sometimes so bad it feels like it could shake a filling loose. ;)



Customer: replied 6 years ago.
will check out things out tomorrow after church.............
Expert:  Bill replied 6 years ago.

OK, Let me know...Clean the throttle body initially. Of course reading scan date would be extremely helpful however I'm betting the vibration is the motor mounts and the stumble is either the carbon in the throttle body or a slewed o2 sensor.


Customer: replied 6 years ago.
what do you normally clean out the throttle body with?
Expert:  Bill replied 6 years ago.
Throttle body or carb cleaner and a rag. it is available at any auto parts store or even most department stores in the auto department.
Bill and 5 other Chevy Specialists are ready to help you
Customer: replied 6 years ago.
Raining today.....when it clears back at you
Expert:  Bill replied 6 years ago.

Roger that.

Happy 4th!


Customer: replied 6 years ago.

Hi Bill, will accept your answer. Just cracked my ribs at the cottage a couple of days and will not be able to bend over the fender to get at my Throttle body......

Thanks for your professionalism.......Jazz

Customer: replied 5 years ago.

tHIS SHOULD BE CLOSED. The computer had to be reset and downloaded . worked fine after that.

should close this out.....Thanks again.....