There are other threads about PCMforless, but this is a bit more specific than I've read about and I want to see what others think.

Stock with my 07, about 22,000 mi, I was getting 14.6 to 14.9 mpg on my normal everyday driving. I then took advantage of the $99 Volant intake for the 07's. After a couple of tanks I was okay with the bump to about 15.2 mpg on my normal everyday driving. Being pleased with that, I sent my PCM in for a tune. Felt different in a good way. Unfortunately, driving pretty conservatively like I always have, I can't even break 14 mpg now. How did I lose mileage? I really, truly don't feel I've been driving differently. Plus, I could see getting normal MPG, but losing with two mods that usually help? BTW, It's been several fill ups and about a month.
I tried disconnecting both battery terminals for 30 min. I ran a tank with Chevron fuel system cleaner. I changed from my normal Chevron station to a Shell station. I even inflated to 36 psi on my tires. With all this, I still calculated 13.9 mpg last night.
Kelly says they can try again with a bit different tune if I want. What do you think? Any suggestions or ideas I've overlooked? She says she hasn't had this problem? EVERYONE has seen improvement?

Thanks for reading!

 

Soooooo, I'm on my own then? Nothing left to try but be without my H3 for a week while I send my pcm back?

 

Wish I could help. I'm waiting for a re-tune after I get my new tires. I left a post asking for advice on max tire size for my 18" stock H3x wheels, yet have got no response. So I know how ya feel when nobody throws ya a bone. Good luck, hope your re-re-tune works out for you.

 

well, from my point of view it sounds like they gave you a wrong tuneup on your pcm, it happens, I guess you have to keep trying until they get it right

 

Send the PCM back and let them confirm if there was a problem, do the loaner and you have no down time.

BTW. disconnecting the battery cables does nothing accept reset the PCM, it does not change the data stored inside. It is like a restart on the computer, it might get rid of a glitch or voltage bug, but it doesn't reprogram any tuning.

You also did not mention the tune you had done. If you tuned it for 89 or 93 octane, and run a grade below that, that can impact efficiency. IMHO 36PSI is too low for street driving, and I'm thinking weather changes are also in the mix, but first start with the simple stuff and have the PCM re-looked at.

Good luck.

 

I thought about one but i'm now leaning towards a Jet Performance module. I want something i can unplug and remove before i take it in to the dealer for maint.