2006 Chevy Trailblazer Are spark plugs the problem?

DSTILES99

MEMBER
2006 CHEVROLET TRAILBLAZER
6 CYL
2WD
AUTOMATIC
70,000 MILES

I have an 06 Trailblazer and about 2 months ago the mpg dropped from 20 to 17.5. I checked the tire pressures, changed the air filter, and used a can of injector cleaner at the next fill-up. No changes, after those and decided to change the spark plugs.

I used Bosch +4 Platinum to replace the OEM plugs and now I have a check engine light indicating an O2 sensor problem. The car runs fine. Would these plugs cause the O2 sensor to fail or is the sensor bad?

Thursday, March 18th, 2010 AT 2:24 PM

1 Reply

CARADIODOC

MECHANIC
34,330 POSTS

The sure way to check the oxygen sensors is to have your machanic connect a hand-held computer, called a scanner, to watch what the O2 sensors are reporting. They should switch from rich to lean to rich a few times per second. If one of them is not responding properly, it will affect fuel metering and emissions.

Based on readings detected by the O2 sensors, the Engine Computer can adjust fuel delivery plus or minus around 10 percent beyond designed-in values.

Caradiodoc

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Thursday, March 18th, 2010 AT 8:12 PM