X Type misfire

[ricky158]

I hope somebody can help before I pull the remaining 2 hairs out! I have a 2 litre petrol X Type of 2003 vintage and have owned it for 7 years. Over the last 12 months I have experienced a recurring problem, which my usual garage and 2 specialist garages have been unable to solve, despite a number of parts being replaced. When the car is driven at motorway speeds it operates as normal, until you have a break! Within 5 minutes of re starting the engine misfires and the engine management light comes on. All then returns to normal, except that you have to keep the speed down to 60 mph, [limp home? ]. Three separate garages have put it on their diagnostics and come up with the same problem, ' lean on both banks '. Nobody has so far been able to cure it despite one bank of oxy censors, new plugs, breather pipe and manifold gaskets. HELP!

[J44EAG]

Old spark plugs which are worn will kill coil packs dead. Have you changed any coils?

My V6 S-type would misfire at 1500 and 2300 RPM when accelerated under load up a hill. .A new set of plugs and itemising which coils were duds, cured the issue.

Regret to say not come across your "lean on both banks" issue. I would be tempted to try some injector cleaner and some Cataclean which really does help clean out cats. It could well be they may be rather blocked.

Check the tightness of the jubilee clips on the airflow meter and at the throttle body. Also the condition of the air trunking breather hoses.

Does your outside air temperature on the heater panel show a sensible reading?

Do you have the MOT emission figures to hand? That can be quite revealing.

Mike K

[ricky158]

Thanks for the suggestions Mike. New spark plugs fitted last week by Jag. specialist, I assume that the coil packs were checked? Injector cleaner etc. worth a go but wouldn't the guy last week have suggested this? I don't know but as he said, he was doing the motor engineers thing and 'putting 2 and 2 together and making 5 '! Breather hoses replaced but will re check tightness. Outside air temperature seems accurate. Car MOT'd last week and emissions spot on. Any further thoughts welcome and thanks again.

[J44EAG]

How many PPM on the hydro carbons? The test paperwork will show that. Mine is running at just 1 PPM after the Cataclean additive was used. 80PPM previously. Well worth £12 and an improved car also.

Mike

[ricky158]

Hello again Mike, emission document shows just 2ppm, so no joy there I'm afraid. Thanks for the effort!