Help - Idling problem with V8 Mantara
2004-02-21 by freddy0012002
Hi Guys, I have a May 1996 Mantara with a fuel injected Rover 3.9L V8 - known as a 'Serpentine' engine I believe. I have an intermittent problem with the engine idling. Every so often (about one trip in six) the engine will not idle - it just stalls eg. when pulling up at a junction, the normal running gets very rough and the fuel consumption goes through the roof. This usually lasts for about 20 minutes before it clears. It can sometimes be cleared by restarting the engine (but not always). It can occur from cold or come on when hot. I have cleaned the plenum chamber/butterfly, and cleaned and tested the idle stepper motor/valve. The engine is in good condition and otherwise in good tune. This is a fuel injected engine with an ECU (I think it's the same as the one fitted to the Range Rover V8) so there is no manual idle speed adjustment, just an idle bleed screw - the setting I have checked as OK. I have had the car eight years (from new) and this problem has always been there. I am told one likely possibility is the temperature sensor for the automatic choke going intermittently faulty and causing the ECU to deliver a really rich mixture. Does anybody have any other ideas? It's about time I sorted this one out!!!! Best regards. Mark. Worcester, England