Been having some fuel effiency issue with my truck, and am trying to figure out some basic information to help in the diagnoses.

1. I remember my truck running about 1.5K RPM @ 70 MPH, now it hitting 2.1K RPM @ 70 MPH, which is causing it burn more fuel.

2. I remember my truck running at idle on cold start up at 1 RPM then idleing down to around 700 RPM, but now it runs at 1.1K RPM till the engine temp is up to normal and then it idles down to 700 RPM

Here a list of whats been done to date.

1. New Shocks
2. New Tires
3. New Motor Mounts
4. New Fuel Filter
5. New Plugs / Wire / Cap / Rotor (AC Delco Plugs and Wires)
6. New Thermistat
7. New MAP Sensor
8. New MAF Sensor
9. New TPS Sensor
10. New gaskets around Air Intake Plenum
11. New and seals in Transfer Case
12. Tranmission was flushed last year due to oil contamination due to some leaks. All solenoids at that time tested fine.
13. New Ignition module and Coil.


I'm looking for a base comparison for drivability for this truck. I would love to be able to do a direct comparison of my information from my scanner with someone else. (Link to come to scanner results from testing)

My truck

2002 Chevy Blazer LS 4.3L Vortec V6 (W) 4L60E Transmission (factory stock.) 121,000 Miles. Avg. 220 mile to 250 miles @ 20 gals of gas (regular grade)

 

overdrive is not engaging is what it sounds like to me.

 

you know that total slipped my mine...

 

Update to post.

The transmission is shifting into overdrive as it should, I thinking I need to find a way to reset the shift points in the computer. Anyone have a suggestion on home fix for this, that does not require a major capital investment?