While driving my 06 Odyssey EXL with 62000 km I experienced a shudder/subtle jerkiness when on a slight uphill grade. Pulled over and checked transmission fluid. Hot (from mountain driving), darkened, slight burnt smell. Concerned about transmission failure, found nearest Honda dealer and drove in 2nd gear about 20 miles. Told service advisor that I thought transmission was slipping in OD. Check engine light was on. Technician confirmed problem on road test. Diagnostic revealed misfire in #2 cylinder. Technician noted #2 plug was loose, no wrench required to remove. Insulator on electrode was broken and a small piece was missing. Changed plug and solved problem. Drove 1200 km home and did a 3X trans fluid change. My question is what was causing the jerkiness? I speculate the engine computer was having a brain hemorage due to the misfire and was calling for repeated up/downshifts in rapid succession because engine was misfiring. Would appreciate any input or similar experiences.