Low MPG stumbles @ idle Code P0014

[Nmeraz08]

??? You said the plugs were changed last year. They are good for 100K miles. Don't mess with them unless you want to inspect them or you did 100k miles this past year.



There are a couple other GM approved transfer case fluids besides AT2. Royal Purple makes one and some other I can't remember.

The problem is that my truck is wasting too much gas it gets like 10 miles per gallon.

 

[IllogicTC]

Just remember Auto Trak II is old technology. Modern full synthetics are much more adept at protecting the transfer case.

Sometimes technologies still exist because they're what works best. Still using x86 computer architecture - sure, we've got special extensions like SSE, but the core instruction set is still a design of the 80s, when we could have a bunch more just built-in to the core standard itself.

Rain-sensing systems? Showed up in a 1950-51 concept car, and was experimented with in 1958 by Cadillac (to operate the convertible top automatically).

Synthetic lubricants? After attempts during WWII, a scientist incidentally discovered PAO during an experiment at Mobil in 1949. That would mean this year synthetic lubrication is ready to retire. Finally patented in 1960, which still makes synthetic lubricants wayyyy over the hill.

 

[Nmeraz08]

Sometimes technologies still exist because they're what works best. Still using x86 computer architecture - sure, we've got special extensions like SSE, but the core instruction set is still a design of the 80s, when we could have a bunch more just built-in to the core standard itself.

Rain-sensing systems? Showed up in a 1950-51 concept car, and was experimented with in 1958 by Cadillac (to operate the convertible top automatically).

Synthetic lubricants? After attempts during WWII, a scientist incidentally discovered PAO during an experiment at Mobil in 1949. That would mean this year synthetic lubrication is ready to retire. Finally patented in 1960, which still makes synthetic lubricants wayyyy over the hill.

Do you know what could be a main reason why my trailblazer wastes a lot of gas??

 

[IllogicTC]

Do you know what could be a main reason why my trailblazer wastes a lot of gas??

It could be any number of reasons.

-Bad/dirty/clogged air filter.
-Old spark plugs
-Wrong oil weight
-Throttle body needs cleaned
-Bad/Dirty/Clogged fuel injectors
-Possibly just time to run a few tanks of Top Tier fuel (visit toptiergas.com for a list of stations utilizing the program), Chevron seems a fairly popular recommendation.
-If top-tier gas isn't available, get a container of Techron at an auto store. The 20-oz version is pretty expensive, but treats up to 20 gallons of gas. Follow the instructions on the bottle. Tank is actually 22 gallons instead of 20 but I don't think that'd make a huge difference.
-Differential gearing ratios. RPO code GU6 should have best mileage, GT4 is mid-level relatively-speaking, GT5 would make you consume the most fuel for a given speed.
-Any number of other things.

A big, important, easy to fix one: driving habits! I am not sure if you've ever heard the term "hypermiling," but there's whole forums and websites devoted to the phenomenon of altering your driving habits to maximize your fuel economy. Everything from keeping your windows up, to keeping the A/C off (did you know if defrost or defrost + floor is running in your Trailvoy, no matter what heat level, the compressor is on?). A common thing people parrot around here is to try keeping the tach at 2k or under. It makes your acceleration go slow, but can work wonders. If you're using the cruise control resume function, don't activate it until you've manually accelerated to about how fast you were previously going; cruise tends to get pretty heavy on the throttle when resuming. Also on steep hills, disengage cruise and control it manually. Cruise will sometimes kick down to 2nd gear on a steeper hill at 55 MPH (runs engine at 4k on my GT4) to try keeping speed, and STILL runs 5 under the setting. You can afford to drop down 5MPH on a steeper grade and use a light foot, usually won't shift below 3rd gear then.