I have a Ford Scorpio 2.0i K plate automatic that will sometimes hesitate when starting off but will then suddenly surge forward. The engine does not increase revs at first but then takes off and is difficult to stop. I have also experienced surging on a high speed motorway run.
Also the cruise control will turn itself on at will. Are the two connected or not and has anyone any ideas what the problem may be. The local dealer didn't.
Thanks
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The surge is the ECU compensating for the hesitation and trying to burn off unburned fuel by adding more air to it. There is something wrong with your fuel injection system somewhere. The place to start looking is the throttle body which might be gunged up. If you ahver a problem in the injection system, this would explain why the cruise control cannot work properly. The cruise is unlikely to have the same problems as that of the Ford Explorer because it's a completely different system. German rather than American.
HJ
HJ
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The surge is the ECU compensating for the hesitation and trying to burn off unburned fuel by adding more air to it. There is something wrong with your fuel injection system somewhere. The place to start looking is the throttle body which might be gunged up. If you ahver a problem in the injection system, this would explain why the cruise control cannot work properly. The cruise is unlikely to have the same problems as that of the Ford Explorer because it's a completely different system. German rather than American.
HJ
HJ
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Dear john,
I presume your engine is 2.0 D.O.H.C. twin cam 8 valve. They are notorious for idle concerns. HJ is right when he suggests cleaning the throttle body but also the idle by-pass screw gunges up too and the engine loses its base idle.
you may also have a sensor problem probably the manifold pressure sensor it would be helpful if you took it to a specialist who could read any possible fault codes from your engine management module.
sometimes these engines will misbehave one day and be perfectly o.k. the next with no adjustment so be careful about what work is done!!
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I have experienced the same problem with my R plate 2.9 auto. The local dealer has replaced the idling sensor and the radiator(due to bulging at the bottom) and the problem seems to have gone, until yesterday. I again experienced hesistancy and slight surging. I have been telling the garage all along that I think it is an injector problem but the deny this. I will take HJ's response to the garage to see what they say.I would like to know if HJ's suggestion cures problem.
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john
I have just read your message again the hesitation starting off if it is like a severe "flat spot" could indicate a faulty throttle potentiometer.
Also the cruise control fault sounds like water ingress into the fuse box causing a short circuit do the sidelights stay on by themselves too sometimes?
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Trevor
Thanks for your reply. Two fuse boxes have been replaced due to wter ingress. Both had better covers than the original. Yes the cruise light stays on until the side lights are turned on. the local dealer says it may be a wiring fault and could cost £400 to sort out!. The surging problem only occurs from cold.
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