Have done everything, but fuel economy has DECREASED
Purchased this vehicle 2 years ago. In 2010, I was
getting great fuel economy, I had no complaints.
500-600lms (300-360 miles) on a tank. I changed
the air filter in August, and was not getting 600-
700 kms on a tank. (360-420 miles) on highway
use. A personal best of 740kms on a tank actually.
Roll into 2011. My mileage was poorer, (I assumed
it was the "Winter Gas, and the additives) then I
added 4 new tires in April, and always keep to
correct pressure. Tires are Firestone
My mileage was barely 500kms now, on perfect
highway conditions. I brought it in for a full tune
up... One of the O2 sensor was bad. Had this
replaced. Replaced all plugs with OEM Champion
plugs. Replaced the fuel filter, and air filter again.
Also had a universal joint, and rear axle seal
replaced, as it was beginning to leak.
IT's the 4.2L SLE 4x4 model. I started a
spreadsheet to keep track of my fuel economy. I
burn 15L-16L per 100km on highway (at speed
limit) . This is averaging 14-155MPG on highway.
CITY MPG - it is now getting 9.5MPG in the city. It
burns 24L per 100KMS. This means I can barely
go 300kms in town for $95.00 (30 cents a KM)
Compared to what I got last August/September,
(21MPG or 10.7L per 100km) this is just horrible..
Frustrated, don't know what to do next. Love my
truck, need to remedy - any helpful advice? So
I did a custom tune of my PCM (Wait4Me Custom Tunes out of IN) on my 03 Chevy Trailblazer LT. I can pull 25 MPG on longer trips if I am steady on the pedal. I'd replace your plugs with AC-Delco's. What oil are you running? Amsoil is my 1st choice, then Mobil1. Tire pressure is VERY important and so is the AIrfilter (AC-Delco), which are 2 areas you've already covered. I also removed my roof racks to cut down on resistance. The grade/type of gas you use has an effect. Do you run a fuel system cleaner with your oil changes? I run Seafoam or Chevron for my fuel system. Hope this helps.
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