Hi just purchased a 2006 Corolla with 255000 kilometres . It was running a little rough when I got it .But I have since changed the spark plugs ,air filter ,cleaned the mass airflow sensor and the throttle body also ran a couple of bottles of fuel injector cleaner . Seems to be running a lot better now . The only problem I have is at freeway speeds if I drop down to 80 K and then accelerate back to 100 K I feel a knock I'm thinking it's the transmission as I can feel it under my feet . If I accelerate with the O/d off it doesn't happen but then when I switch the O/d back on it does it sometimes as it goes into fourth . Could it be the transmission mount ?
