I'm still going with the TPS. I had the same problem and it was intermittent and seemed to occur when it was damp or raining. I highly recommend all vanners get a ScanGauge. This device is a basic diagnostic tool and will read fault codes and reset the "check engine light". It also monitors all kinds of stuff that I don't know WTF it's telling me. But I do know what TPS is and that any value above zero, when my foot is not on the footfeed, is not good.
ScanGauge - Trip Computer + Digitial Gauges + ScanTools Better than a wheelchock, but also more expensive. I've got the original ScanGauge, which is almost twice as tall as the new ones. I have it mounted with Velcro™ on my dash. The new ones are way more cool and trimmer.
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Disclaimer: I currently own no shares of stock in scanGauge and to the best of my knowledge I never have. I never have or never even thought of being a member of the Communist Party to the best of my knowledge. I may cast my presidential vote for a member of the Communist Party in November or I may vote green.