Bloody Misfiring!!!

[zzr1200]

If the damn thing doesn't stop misfiring I'm gonna sell it! So far I've changed the HT cap, leads, spark plugs, coil. Cleaned the idle control valve, checked for air leaks, checked the throttle pot, cleaned up the rotor cap numerous times, cleaned the air filter and checked the leads to the HEGO sensors. HELP!!! Has anybody carried out a conversion of any kind on the ignition system? It is now beginning to spoil my enjoyment of what is a great car(Chimp 400 1997)

[T88CAN]

Try an Emmissions test at your friendly MOT station could well be Lamda sensors ( it was on mine) TONY

[zzr1200]

Is it possible to clean the sensors on the V8? My V6 Mondeo had that problem and my local Ford dealer cleaned them.

[GreenV8S]

Are you using any particular method to track the fault down, or just tackling it by trial and error? Unless you know what you're doing, I recommend taking it to a specialist. Otherwise you risk spending a lot of time and money fixing things that weren't broke.

[hut49]

Try telling us about the symptoms and let's see if we can help - "misfiring" could cover a multitude of faults. Be specific and save yourself a packet.

[joospeed]

GreenV8S said:

Are you using any particular method to track the fault down, or just tackling it by trial and error? Unless you know what you're doing, I recommend taking it to a specialist. Otherwise you risk spending a lot of time and money fixing things that weren't broke.

good call .. if you're struggling why not call in a professional? .. what if it's the earth under the centre console anyway, or the one on the back of the cylinder head, or because you've set the throttle pot with the engine off not running etc etc .. 10 mins fix for free at most garages, then you'd feel a little silly at trying to fix it yourself and spending all that money for no reason. Seek help, then you can go back to enjoying your car for it's intended purpose .. driving.

[Trefor]

Plug extenders?

[mark c]

I may be talk total B*ll*cks here but... having recently had running problems after it went in for a service and having gone through a number of checks and changes myself with little or no effect I took the plugs out to check them and found the gap hadn't been set right by the guys who did the service, think it should be 35 thou but was set to 25 thou. Put them all back after increasing the gap to 35 and it definiely runs a lot smoother! Whether it was the gap or something else I don't know...

Anyone out there an expert on plug gaps?

Cheers,

Mark

[philr]

Have you had (or done yourself) the base idle checked. Mine was running very badly and even misfiring in its worst cases. Turned out to be the base idle being way off.

[swisstoni]

I've spent about a grand on 'experts' trying to fix a misfire (which rather guttingly appeared 2 weeks after an £800 main dealer service) and although I've had improvments I've still got a hesitation at about 2K rpm in every gear.

[colinrob]

mine was missing above 5000 revs (again this was after it was serviced and new cam and mark adams chip was also fitted)got new plug extentions, rotor arm and dist cap now revs to 6000 (have'nt tried any higher) without missing

[zzr1200]

Thanks everyone! I'm gonna try changing the plug extenders first and then get the emissions checked by a garage to see if it is the HEGO sensors. The strange thing is that it only does it when it has warmed up and then only randomly. I'll post an update of my findings.