Super Highway Mode

I've been using this technique for a while now and I have a question. I'm sorry if it's been addressed already 'cause I know I've seen it here before. Anyway, I'm driving to work today -got my rpms at 1280 or so and timing at 14. Then I hear the engine go up in rpms, similar to a regular transmission when you punch it and it backshifts to a lower gear. I know it's done this before but today is the first time I actually heard it. I was getting great mpg and then it dropped way down. I never changed my position on the accelerator. Can anyone explain to me what is going on at that point?

 

If you're talking temperature it was 3 above 0 when I drove to work.

 

Yeah, I kind of figured that out later. Sometimes I have senior moments.

I guess my question is why did it do that? I never changed position on the accelerator pedal. It just jumped from 14 degrees to 21 or so all on its own.

 

I can't honestly say. But I was about five minutes into my trip but it was terribly cold. I use an EBH but even then it takes awhile. I'm gonna guestimate about 140 degrees F.