Slight miss at idle - Please help

[Ext User(Petesin)]

Ford 2002 AUIII utility
Auto
120 000km

When idling, every 5 seconds or so the engine seems to miss fire slightly.
May be doing same at higher revs but is unnoticeable when driving What
could this be caused by?

Replaced fuel filter on weekend even though had only done 6000km. (why
don't they make it easier to see if there is much shit in it)
Cleaned throttle body with carb cleaner spray (was some blackness around
throttle, nothing that seemed too excessive).
Ignition coil recently replaced (4 weeks ago)
Plugs done 15 000km (10months)
Leads tested when ignition coil replaced (came up fine)

A couple of times recently while just driving along it has stopped. Very
little 'splutter' and then nothing. When I pull over it fires straight away
and off I go. Happened twice before coil replacement and 3 times since.

Any ideas?
Electrical? Fuel?
I haven't go the tools nor the mechanical ability (though I'm willing to
try) to test compression. Could this an issue?

Thanks in advance!
Petesin

[Ext User(sgam@hotmail.com)]

On Oct 25, 4:40 pm, "Petesin" <wh@tthefuck> wrote:
> Ford 2002 AUIII utility
> Auto
> 120 000km
>
> When idling, every 5 seconds or so the engine seems to miss fire slightly.
> May be doing same at higher revs but is unnoticeable when driving What
> could this be caused by?
>
> Replaced fuel filter on weekend even though had only done 6000km. (why
> don't they make it easier to see if there is much shit in it)
> Cleaned throttle body with carb cleaner spray (was some blackness around
> throttle, nothing that seemed too excessive).
> Ignition coil recently replaced (4 weeks ago)
> Plugs done 15 000km (10months)
> Leads tested when ignition coil replaced (came up fine)
>
> A couple of times recently while just driving along it has stopped. Very
> little 'splutter' and then nothing. When I pull over it fires straight away
> and off I go. Happened twice before coil replacement and 3 times since.
>
> Any ideas?
> Electrical? Fuel?
> I haven't go the tools nor the mechanical ability (though I'm willing to
> try) to test compression. Could this an issue?

Without the tools, I'd be taking it to a trusted mechanic, and asking
them to sort it out.
>
> Thanks in advance!
> Petesin

Leads can let go without much warning. Typically they have a life of
80-100,000 k's. That would be my guess. Typical diagnostic: Pull
each plug & inspect. Turn engine over with a plug out and see if it
fires. If it doesn't, see if it's the plug, or if the lead is the
issue. If the lead isn't the issue, then check distributor cap and
rotor (IIRC, the AU has a dizzy, not coil packs?). IOW, work from the
engine, back to the source of spark, bit by bit to see where the
problem originates.

At 120,000k it's about time to replace your oxy-sensor - but they can
be tested before throwing money at stuff willy-nilly.

Cheers,
Steve

[Ext User(John_H)]

Petesin wrote:

>Ford 2002 AUIII utility
>Auto
>120 000km

>
>Any ideas?
>Electrical? Fuel?
>I haven't go the tools nor the mechanical ability (though I'm willing to
>try) to test compression. Could this an issue?

Without being familiar with the model... your fault description
suggests that testing for vacuum leaks might be worthwhile. Start by
pinching off the hose to the brake servo and see if that makes a
difference. There will probably also be a largish vacuum hose to the
transmission.

--
John H

[Ext User(Noddy)]

"Petesin" <wh@tthefuck> wrote in message
news:47203a7b$0$20610$afc38c87@news.optusnet.com.a u...

> Any ideas?
> Electrical? Fuel?
> I haven't go the tools nor the mechanical ability (though I'm willing to
> try) to test compression. Could this an issue?

Highly unlikely.

If you're sure the ignition system is in good shape and things like plug
gaps set correctly, then you could check your battery voltage (with the
engine running), and also look for loose or corroded wiring connections at
every connection you can find around the engine.

--
Regards,
Noddy.

[Ext User(ausmartin)]

Probably either crap spark plugs,

Try Denso or NGK - others are crap.
or
as the others say Leads OR sensor for the timming.

But my moneys on crap spark plugs Falcons always have trouble with
certain brands/grades when hot & idling

[Ext User(Jason James)]

"Petesin" <wh@tthefuck> wrote in message
news:47203a7b$0$20610$afc38c87@news.optusnet.com.a u...
> Ford 2002 AUIII utility
> Auto
> 120 000km
>
> When idling, every 5 seconds or so the engine seems to miss fire slightly.
> May be doing same at higher revs but is unnoticeable when driving What
> could this be caused by?

Once I had a situation where the battery terminal-clamp had become loose on
the Camry. The battery would disconnect itself on and off while I drove
along. There were no warning lights for this fault. The way I picked-up on
it was I used the high-beam flasher, and for that instant the alternator
which was essentially suppying 12v for the car on its own,.couldnt supply
enough current for the cold-filament current inrush,..and the engine
snuffed. This maybe your problem>>clean and tighten all heavy battery cable
connections/battery etc.

Jason