My Avenis (2.0 Vtti) has done 112,000 miles and over the past six months has become irratic when idling. Ussually, when the engine is warm, and you are stationery, it will idle fine - other days though it is much differeent. Watching the rev meter the revs will drop to about the 100rpm mark (so it nearly stalls)- then the engine will rev to 2,000rpm, and gradually drop back to 100rpm - and the cycle starts over again - people must think I am reving for the sake of it! Now it is getting worse - the engine will stall as soon as you come to a stop - very good when you are half way round a roundabout! The Toytoa garage wants £500 just to look at it - something about inepsecting the internals of the engine - and told me that it may need a new engine - which at 112,000 is a bit odd! they claim it a known issue! My local garage (indpendnet) told me that he has seen this problem on an Aveniis before - and that filling up with Redex solved it. so a few questions a. How often should I put Redex in my car? Every fill up? b. does Redex do any harm? c. anyone else had similar problems?