miss firing

[thegasman]

Advice please Chimaera 400

Car running perfect just before xmas.Started up this morning all ok left idling for a few mins then drove off up the road.A few mins later and she was running like a pig very bad misfire and not much power.Managed to limp home opened the bonnet and found no2 spark plug lead off dangling over the exhaust manifold put it back on cranked over the engine which seemed to take ages to start and then she fired and seemed ok.Quick spin up the road all ok then same problem lack of power not running on all cylinders limped back ok.Checked under bonnet all leads ok but just ticking over and very lumpy.Been serviced this year 2000 miles ago and also all new leads cap rotor arm and coil pleas any ideas

Thanks Mark

[GreenV8S]

Most likely explanation you have fouled the plug, less likely the HT lead has been damaged while it was dangling around.

Suggest you check that the plug is still firmly seated at *both* ends, check the other plugs too. If the problem is still there, take #2 plug out and see what state it's in. If it looks wet/oily, fit a new replacement.

[pwd95]

If it has been left standing for a number of weeks it could be any number of electrical components corroded. Which in turn could be affecting the fuel system or the ignition system. Good luck.

[Cider Andy]

If the ECU has detected the misfire it may have gone into 'limp home' mode and need resetting. Try disconnecting it and reconnecting it to clear the fault. Better still, check it first with a fault code reader, if you have one.

[thegasman]

Many thanks for your help tried all this today but still the same although engine seems to tick over ok for a while then underload will mis fire and become very lumpy loosing power and trying to cut out back to the drawing board.

Cheers Mark

[thegasman]

Many thanks for your help tried all this today but still the same although engine seems to tick over ok for a while then underload will mis fire and become very lumpy loosing power and trying to cut out back to the drawing board.

Cheers Mark

[spyschim]

mine has done this twice now in three years it was the fuel pump relays i have bought a few and allways keep two in car as spares (the two silver relays hanging over battery about £6 each)

[JonathanT]

Probably worth your while to check that all the leads are correctly seated at both ends (especially if they've all been changed recently). I think the rubber boots are airtight so they can easily push themselves off.

I had similar and found I could push two leads further onto the rotor cap which appears to have solved my problem. Everything looked find on first glance.