[dav968]

Wow, that is AWESOME!!!
Maybe one day my wife will agree to getting a coupe 968 and doing the same. A man can always dream.

Yep, I do use premium from large brand gas stations only. I've had the car for about 10 years now, so don't think it's a fuel issue. Last year I replaced the pickup and level sending unit in the tank, and saw that the tank looked nice and clean. I did put in 2 bottles of Techron to clean injectors/combustion chamber when I filled last time, something I do once or twice a year to try to avoid buildup. I pulled spark plugs when doing sensor replacements last weekend, and all the plugs looked really good still, have never had an issue with buildup on them in the past.

I think something in the evaporative emissions system is the culprit, but that is still just a guess.

So, tried driving yesterday with the gas cap loose. 40 mile trip to a client location in morning produced no error codes at all. On return trip though, I got an error code on both knock sensors, but no hesitation while driving.
As a little more back info, before getting the Durametric, I also changes out the cap, rotor, wires and plugs, twice, trying to resolve the hesitation issue. Other than the coil, I think the ignition side of the equation is not the source of hesitation.
This weekend I'll see if I can figure out how to disconnect the evap system and see if I can isolate that as being or not being the cause.

I have a long trip up to an autocross this Saturday, so we'll see how that goes. Running hard and on a less full tank doesn't seem to cause any hesitation, so think it will perform fine during autocrosses again this year. Be interesting to be able to read codes and see if all is doing as well during the event as I feel it has by seat of pants.