Losing power

[r67_vette]

Greeting

2008 Edge SEL 3.5l  Auto  AWD 120k miles

At 85k I installed new plugs and air filter.  Lately I've noticed the trans has been downshifting to maintain speed going up hills that previously it just stayed in high gear.  I have noticed at times the trans has actually shifted down 2 gears.  This is happening with cruise control on so I would think that my right foot has nothing to do with this.  Is it time to change the plugs again?

TIA

Gary

[circatee]

I am not a mechanic, and thus do not know the answer. 

However, like most things, I wonder if anything is related to the 'quality' of the spark plugs. Also, when those are changed, is an oil change needed, too? 

[enigma-2]

Air, fuel, ignition.

Doubt the plugs are the problem.

 

AWD? Ever change the fluid?

Tranny fluid change?

-> mass air flow sensor dirty

-> 35k miles on the air filter. (Filter can get dirty in just a few miles under severe conditions).

-> injectors dirty? (Pour in a can of Techron Concentrate Plus Fuel System Cleaner).

[r67_vette]

enigma-2

Thanks for your response.  I changed the fluid in the rear, but not the trans last year.  There is no drain plug in the AWD power transfer unit so not sure how to get that changed.  Air filter is good. Guess I will try a can of the Techron.  Per the last 2k miles I have averaged 40 mph with a 21 mpg average per the information panel

Gary

[enigma-2]

Local garage can pump the fluid through fill plug, using the same equipment they use to change the read differential. My Ford garage charges somewhere between $60-$80 (forget exact as usually have it done during oil change, etc.).

 

21 mph with 2008 isn't a bad mpg. Could be cold weather (warm up, short trips) or heavy snow (plowing will reduce mpg). Monitor over a longer period as I get somewhat similar.