Have a 03 V11. Ran great all summer. Let it set for a month while I took the BMW to Montana and now it will not run between 2000-3000 RPM starts and idles. Runs good over 3500. Great wide open. Left cylinder pops and backfires, spits and sputters. Throttle bodies have been synced, TPS adjusted to spec, new plugs, fresh gas. No luck. Just the left cylinder runs poorly and backfires. When I unplug the TPS, the backfire goes away, but of course it will not run below 2000 RPM, but the left cylinder gremlin seems to go away. WTF? When I adjusted the TPS, the voltage seemed to increase in a smooth linear fashion as I rolled the throttle to W.O. Did not appear to jump around, or show any sign that it was not working. Any suggestions? If it is a bad TPS, why just the left side?