code help...
i used a flashpac(?) programmer...not for my truck...to check DTC. last weekend had 10 codes...cleared and drove this week. came up with 6...most of which i think are common when you unhook the AIH, the EBP butterfly, and when you have a tuner. but no Check Engine Light?
the one im having trouble with is P1670. it state something about IDM to PCM communication. i did install a resistor in the IDM would that have something to do with it? the truck runs fine, starts good, but my mileage has seemed to go in the crapper....just changed fuel filters so hopefully it goes back up. i searched the code and found it maybe a relay, but im not sure how to check it. any help would be greatly appreciated


