My 94 Corolla just scraped a pass on its MOT the other day because the tester said the emission levels were up due to not using the car enough. (too many visits just to Tescos).
He said to regularly go up the motorway in *fourth* gear to clean out the engine and catalytic converter.
Also at seventy miles an hour in fourth gear the engine is reving at 4000 rpm or so. Would it also help if when on a 'secondary' road i drove along in *third* gear to keep the revs up, or is the actual 'length' of a journey an important factor?
What would be the 'minimum' distance to travel on a motorway, say once a month (if that's often enough) to keep the converter in good shape? Thanks for any advice on the best way to care for the converter.