I've never reset my PCM in the 3+ years I've had my truck. But after getting my headers it was recommended to me for the purpose of letting the PCM "learn" and integrate my latest mod faster. I thought to myself, that it makes sense, so I did it.
All I can say is WOW. Performance increased dramatically and the biggest thrill so far is my mpg's went up better than 2.5 mpg's. I know I felt some performance gains after the header's (especially in the mid to upper rpm range) and my mpg's went up about .4 mpg's (according to the overhead), but after the reset, the difference was huge.
I've only been riding it for 5 days since the PCM reset, so this is a short term mpg test. However, I take the same route to work & home, so there are NO other variables to consider. I always reset the overhead after fill-ups, and my truck has always gotten 12.4-12.6 ever since I lifted it and got the 35's almost 2 years ago. After3 trips back & forth to work (16 miles each way-mostly in-town with traffic lights) my overhead is saying 15.3!
I'm thinking my PCM maybe didn't just learn my headers alone, but possibly my exhaust, CAI, and e-fan, all of which have been added over the last year and a half.
I don't know if my mpg's are gonna stay up there long term, but the added acceleration my "butt dyno" feels is worth the reset alone. I'm also calculating my mileage since last fill-up on paper, so I'll have confirmation that the over-head is correct. Thereis no reason to think not though, the last time I made a run to the farm up in Ga., (320 miles, almost all highway) I got 14.9 on overhead and 14.97 on paper.
Looks like my in-town driving now is actually better than my highway driving was before.

 

Excuse my ignorance, but how does one go about resetting the PCM? I've done all the mods you did (except the e-fan). It would be nice to get a couple extra mpg's out of mine. I would have to re-calibrate MY "butt-dyno", though. I don't think it's as accurate as yours .

 

Take out the fuse, look on cover of fuse box for PCM, get in and buckle up, turn the key to "on" for about10 seconds (your basically wait for the engine, abs lights, etc. to go off) then turn the key to "start" and hold until you hear 2 chimes (should be about 15 seconds, give or take). The truck won't start BTW, put the fuse back in, and you're ready to go.

 

You're awesome. Thanks...again.

 

Good info...thanks.

Btw, what brand headers did you get?..and where?

 

hmm.... maybe ill do this after the intake....

 

Reseting the PCM is something I never thought of. Thank you for this post.

 

Resetting will always say better gas mileage but it really doesn't get better gas mileage, the readout will keep coming down until it is where it was before the reset.

 

Hate to dispute you, but pad & paper confirmed it. MPG slipped down a tad from my first post, a couple of errands in town, block to block, light to light. Still getting a good bit better mileage though, and the truck still feels like it's pulling better than before the reset.
Readout said 14.9 mpg and after I filled the tank today, I got 14.71 on paper. So I'm still seeing a 2+ mpg gain since the reset.