VTEC-E question, help!

[benfrogg]

93' civic vx. Federally.
So I've had a perplexing thing happen. This has happened before, but I didn't have a gauge to prove my theory.
After driving for about 24 miles, (it was -3at the start of my drive) I was traveling on a flat plane at 40 mph and holding 65mpg on the gauge. Suddenly, an increase in low end torque (I'd estimate about 1/4-1/3 more) and big increase in mpg's. The gauge shot up to 104mpg and stayed there. The car started to accelerate. I hadn't changed throttle position the whole time.
The rest of the drive home, I could hold much higher mpgs at higher speeds and with much less effort up hills. The remaining 10 miles raised my trip mpg by 7mpg's. (total about a 34 mile trip or so)

I have noticed this happen several times on long drives. After 15-20 miles all of a sudden I start getting much better torque without losing lean burn. I couldn't prove it was reality (and not my head) until I was staring at the gauge when it happened.


So, honda experts, what happened?!?!?

I'm thinking vtec. I'm going to head out to the garage now to test the electronics side of it and to pull the valve cover to inspect the components. I've been reading that if the solenoid fails, it fails in the "higher power" mode. That is to say, it fails in the more aggressive, 16valve mode as opposed to the less aggressive, better swirl, almost 12 valve mode. The ecu turns off the solenoid to achieve "higher power" mode. Is this true?
If so, it may explain the problem. However, I have not found any codes so that makes me confused. The book says it will show a code if it fails.

This brings up another question: If I unplug the vtec solenoid, would the car run all the time in the "lower power economy" mode?

So the big question is, is the problem mechanical or electrical or both?


Any other possible scenarios? Could it be something other than vtec? Could it be the ECU? I have a spare one of those I can swap in.
Thanks for the help!
B