I have a very similar issue that just arose this morning on my way to work; I was behind someone driving very slow and when the highway twinned and I went to pass them there was no acceleration at all, mash the gas petal and nothing happened. I put it in neutral and it didn't rev at all and was running a bit unsteadily. I pulled over and shut it off and started it again after a minute or so and it worked fine after that. Seems related to this issue, only at the early stages perhaps.