Darrell, Thanks for doing some great testing. I think I will now remove my WAI as I haven't seen a noticeable benefits ( nor decrease ) with it and your detailed testing proves that its effects are negligible .
You have done a great service for us hypermilers.
all the best L&S
You're welcome, Vic. I kept my WAI, because I think it has to help the engine warm up faster in the Winter. Even with the WAI, my engine doesn't warm up in the Winter until I've traveled ~four miles. That's because I P&G during warmup.