Unusual power loss (not just normal loss due to thinner air) in the mid RPM range, at highway speeds, most noticeable above 6,000'.
1) I have put 106,000 miles on the truck since I purchased it new in '05.
2) I'm familiar with O2 / air pressure issues and their role in power loss at hi elevation/altitude, and drove the vehicle thousands of miles at these higher elevations w/o this more recent, abnormal power loss.
3) The vehicle is a 2005, 4.0L, 6M, 4dr, TRD, tow package.
Eight + months ago when I was away at work a Jiffy Lube told my wife during an oil change, that the truck's injectors were real dirty. We had noticed the signifigant loss of power (downshifting sometimes does not allow speed limit) recently so I took the truck to the local (Durango, CO) dealership and told them the situation. They agreed, and did a fuel injector flush, and service. No change to power loss. Took it back, the dealership said the (one or more) catalytic converter(s) were bad. (no check engine light). After consulting TWF, and other resourses it seemed that the cats were bad; made sense to me. I had a local guy reset my ECU, clean off my MAF, and did a test drive; still the same. He agreed it was probably the cats so I had him put on a Doug Thorley setup. I still can't notice a change to the original issue!
So, what gives?