Posted: Jul 15 2006 at 4:49pm | IP Logged

I have a 05 Titan 4x4 LE and recently self installed a Volant cold air intake and a Airaid throttle body spacer.  The day it was installed the fuel mileage indicator showed my mileage jumped from a previous average of 14.8 to 17.8, then 18.2 at best on a 50 mile run with cruise control set.  Two days later, after towing my boat and also carrying a heavy load in the truck bed, my mileage has consistently showed a average of 13 to 14.5 at best.  Seems the truck computer compensated somehow and actually reduced my mileage.  I have standard exhaust. 

Does the computer have to be reset?

Posted: Jul 15 2006 at 5:36pm | IP Logged

the titan's computer is actually a learning computer, it will adjust to your driving habbits, so being its impossible to be at 100% throttle at all times, the computer will de- tune itself after a little time, you can reset your ECM to start freash, most say to do this about once a month ...

heres the directions on how to reset, ( disconnecting the battery will NOT reset the ECM )

ECU Resetting Procedures

Timing is extremely critical. If it is NOT DONE within the specify time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON. A stop watch or an analog clock with a second’s needle will be useful.

Operations Procedures

1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.
2a. Fully depress the accelerator pedal (HARD).
2b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
4. Fully release the accelerator pedal (while the CEL is still blinking)
5. Wait about 10 second.
6. Fully depress the accelerator pedal and keep it for more than 10 seconds.
7. Fully release the accelerator pedal (The CEL light will continue to blink).
8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.
If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.

Posted: Jul 17 2006 at 8:17pm | IP Logged

I'm sure some will disagree with me, but the best way to get your fuel mileage is to do it the old fashioned way...With a full tank, reset your trip odometer and do the math when you have to fill up again. It will even vary from one tankful to the next so taking an avg of 3-4 tanks isn't a bad idea either.

"Two days later, after towing my boat and also carrying a heavy load in the truck bed, my mileage has consistently showed a average of 13 to 14.5 at best."

Wouldnt you expect it to be lower after towing and hauling?

Posted: Jul 17 2006 at 8:40pm | IP Logged

I appreciate your comments about lower mileage rates with towing or heavier loads and certainly I do expect that result while doing those chores.  However, the mileage did not come up after resetting the mileage computer in the truck and normal driving habits resumed.  My question was could the truck computer somehow have reset itself and the first answer I got from Misery Tom seems to make sense. 

I always check my mileage by odometer and gallons per tank, just was hoping someone might know more about the modifications I made and their effect before I refilled and did the old fashioned test of mpg.  Thanks.

Posted: Jul 18 2006 at 1:41pm | IP Logged

i hope i made sense... cause its 100% true lol

but, on a serious note, since adding a CAI gives the engine more air, it will also cause the computer to put in more gas to make the mixture correct, so adding a CAI doesnt really get you better MPG like most ppl seem to think, just a little more power.