Well my VX got some minor hesitation when Im cruising on the highway and trying to maintain a steady 62mph. Could it be the IACV having to be clean, or the injector needing to be clean with either some acetone or having them clean by a specialist. The o2 sensor have been done, so its not a problem about lean burn. If you have any other idea, go ahead .
I tried using acetone to clean the carbon deposits off of the head of my 1987 Civic. It worked a little bit, but not nearly as good as Berryman B-12 Chemtool (which is a mixture of Acetone, Methyl Ethel Ketones, Xylenes, and maybe Toulene- basically just all the paint thinners combined). I'd recommend B-12 for cleaning the injectors out.
Guys, be careful with that B-12 stuff. I used some last month in my bike - Suzuki Katana that had plugged carbs - the only thing it did was to dissolve rubber diaphragm in the petcock, so it had to be replaced as a $100 assembly, and then I still had to take the carbs off to clean. I'm sure B12 is fine for cleaning metal parts, but it will damage rubber gaskets if it's concentrated.