If that doesn't work, I would run through all of the fuses and make sure that they are all good.
Check the wiring harness that runs by the A/C accumulator - chafing is known to happen there.
Next, pull off the upper intake - this will give you a chance to check out the supply line from the filter manager to the IP....rodents also like to build nests under there and eat through the main wiring harness...
BTW - stepping up to a DMAX will feel great....except for that one day per month when the payment comes out....
Give the 6.5 a chance, blow it to kingdom come, and then come join me on the 'other' side....LOL!