This isn't a problem really. The car starts and runs OK, with slight roughness at idle. Its just that when picking up speed at more than half throttle, there is a noticable stepping effect, like the engine gathers speed, pauses a moment, and then continues accelerating. It happens in 2-3 second cycles and is not related to gear shifts. Its usually very mild, and not noticable when driving in 'economy' mode, so I'm wondering if anyone else has this. I'm guessing its fuel system/ECU related?

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1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma