Not sure about the OP, but I did another round trip to Idaho for family stuff last weekend and totalled tad over 1000mi. Had 4 of us in the EX, our luggage, and some sound equipment so we weren't running heavy at all. I don't like to run faster than 70-75mph in this thing, so going down the highway versus the freeway made no difference in my MPGs. Going over, we got just shy of 14 and coming home we averaged just under 13mpg. This thing ain't exactly a Geo Metro, but once again, my wife did comment that she's glad I finally bought a vehicle that is comfortable and roomy enough for road trips. I'm 6'3 and my boys are 6'4 (17yo) and 6'0 (13yo). Now, toss in my daughter, the family dog, and all our personal stuff and we can still get plenty comfy in this rig. I can afford the fuel......

 

Not to mention it would take 2 fuel efficient vehicle to do what one X can! Which would negate the reason for having a fuel efficient car. Yes the X is excellent at what it can do!

 

I would suggest:

Compression and leak down test on all cylinders....expecially #10.

Being in a cold environment you probably have a 195 degree tstat. That could make your clutch fan run on all the time as its calibrated for a 185 degree tstat.

Also the maf has a temp sensor in it and pcm "corrects" for air temp increase between maf and intake valves. A 195 tstat will heat air more than a 185 tstat.

Put newly refurbished injectors in, I suspect you have a few bad ones.

Put a vacuum guage on motor to get idle vacuum numbers. Anything below 14 in hg at 1000 ft elevation is poor.

Drive excursion with vacuum guage hooked up and do a vacuum analysis.

 

Sorry for the late reply.

I’ve just stretched the EX’s legs. I got 520 miles to a full tank, all highway miles.

It’s safe to say my EX is now firing on all 10 cylinders very nicely