wbalester

Ok. Here's the answer. While on an extended road trip recently, my check engine idiot light came on while accelerating from 65 mph. The day before, the car had started shuddering slightly when accelerating from stop, but no engine light. Took car to a local shop, they plugged in the computer and codes said one bad coil. Changed the coil and car has run correctly ever since. Mileage back up where it should be. The question now is, Why didn't the engine light come on sooner? Seems to me a bad coil should be sensed immediately. I ran the car for 6-7 months with a bad coil and 25% poorer mileage than I should have, but with no indication. Somethings not right here.

Thanks for the input. Everything but changing the plugs was taken care of before I posted the first one last week. The weather conditions, cold, rain, snow, etc., were not this magnitude of problem last winter. Just a small drop similar to what everybody seems to experience. It all started late summer, early fall. I'm consistently getting about 22 mpg city right now, and took a road trip last week, 650 miles round trip, stayed below 65 mph, and averaged less than 36 mpg, little or no precipitation. So, now I'm gonna change the plugs and see if that helps. I'll let you know.

Bought my 2010 FFH last Feb. with 69K miles, from a local dealer. On the ride home it got 41 mpg, in the snow. Since then has run perfectly. Generally averaging 38-40 mpg, which was fine. However, in September, I noticed the mpg per trip was dropping, and the overall mpg along with it. Recently, since about Thanksgiving, the mileage is consistently below 30 mpg per trip, sometimes as low as 20. Long term MPG is below 32. No check engine light or other indication of any problem. Took it to a dealer, different one from where I bought it, and they could find no problem. Charged me $100 for nothing. Just turned 80K miles. Seems to be running maybe a little rougher than when I got it, but still is just fine. Has anyone else experienced anything similar? And is there a list anywhere of technicians who are better than others at diagnosing hybrids, listed by locality or region? Could this be transmission related instead of engine? Anything?