Okay, I know that just about everyone with a 205 / 309 GTI (or anything else with an XU injection engine) has this problem... rough idling, stalling when cold (or even when warm) - but does anyone know WHY? Or more specifically, what goes wrong with age that causes these symptoms? I assume these engines didn't do it when they were new, or nobody would have bought one!
My theory: as the engine gets older and more worn, the running friction decreases so the owner has to gradually turn down the idle speed adjustment to keep the (warm) idle speed in spec. This means the engine needs less and less air to keep it running, and eventually the air flow rate is so low at idle that it's outside of the range that the AF meter can measure properly, or off the end of the ECU's fuelling map, so it gets the fuelling all wrong.
Can anyone confirm / deny this theory? Or has anyone managed to cure the problem?
GTI rough idle / stalling
Moderator: RichardW
As a quick "temp" fix, I tried cleaning the butterfly valve on the end of the throttle cable by spraying some carb clearner into it whilst holding the valve open, this worked for a while, however havent come up with anything yet - except driving around with my foot covering the throttle pedal whilst slowing down.......