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Only firing on 3 cylinders (occasionally)

PRJ

PRJ

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Let the expense begin...

All has been fine with my Turbo until the other day when on the M23 in 4th gear the revs dropped suddenly and I appeared to be down to 3 cylinders. It cleared itself within a few seconds and all was fine until this morning. Fired her up from cold and it was only firing on 3 again.Wasn't stalling, but only just hanging on. Turned off and then fired up again, with the same problem. Left it for a couple of mins, so the immobiliser had kicked in again and fired up and all fine. Have just dropped my daughter at nursery and all was fine when I restarted and then suddenly in 4th gear, it's died again. Switched off and on a number of times (making sure immoboliser had engaged before trying each time) and still the same problem. Then all of a sudden I press the throttle and all 4 cyclinders are back. Ideas anyone?
 
It's most likely an ignition problem. Start with the usual suspects.Plugs, leads etc.

First of all, try to figure out which cylinder isn't firing. Easy enough to do, just unplug one ignition lead at a time until you find the one where the running gets no worst (when you unplug the other 3, you'll probably fing that the engine will stop, as you'll be down to 2 cylinders).

It's also a good idea to check all the plugs, as one may be fouled. That could either be the cause of the misfire, or a symptom of the nasty and expensive thing that's wrong with the insides of your engine.

James
 
Thanks James - Hopefully nothing serious internally. When it's actually running on all four, it's as sweet as usual. Sounds more likely to be electrical/ignition related as you say. He says in hope...
 
That's the most likely. The favourite for a fault that's come on like this is either a breaking down plug lead or a worn/dirty distributor cap.
 
Don't just grab a lead and pull it off with it running - you'll only do it once if you do [;)][FONT=verdana,geneva"] [FONT=verdana,geneva"]It might be worth pulling both ends off all 4 leads and checking all looks clean and tight in there, and that the plugs look OK - one might be broken.[FONT=verdana,geneva"]
 
And if the lead happens to be bad with failing insulation causing the misfire? I've seen a mate get an HT shock from an old Escort, a 944T can only pack more of a kick.
 
What's the problem with that? Ok, it's a high voltage, but there's practically no current, so it isn't going to do you any harm.

I used to use my girlfriend as a spark plug tester when I had my first car. She would hold the plug, and I'd turn the engine over. I no longer have that car. Or that girlfriend [:D]
 
Open up the bonnet at night in the dark. My leads were shorting against the bonnet, but even without the bonnet to arc to the engine bay looked like something out of a Jean Michele Jarre video. Worrying concidering the leads proximity to the fuel rail...
 
if the ignition tests fail, what about a blocked injector? unfortunately a bit harder to diagnose which one, but if ones coming off, you may as well get them all cleaned!
 
B0ll0x - never even made it home tonight. Really does smack of a Dist Cap/HT problem, but have had to abandon it at a hostelry en-route, ready for pick-up and transport to SPC tomorrow. Light-hearted 'German rubbish' comments from white van man who helped push me to the side of the road accepted with grace [:(]. 1 of 9 lives gone...
 
Ah well, at least you still have the Spanish car to get to work tomorrow then.[FONT=verdana,geneva"] [FONT=verdana,geneva"]On the bright side it's always more difficult to confidently fix an intermittent problem.[FONT=verdana,geneva"]
 
Yeah, but the Spanish one is all nice 'n' shiny waiting for someone to buy it, so I don't want to get it all dirty. Besides all that up front torque messes with my senses as I'm just getting used to the 4,000rpm kick from the Linen one
 
ORIGINAL: Mikie_gb

looked like something out of a Jean Michele Jarre video.
Click to expand...

I hope it is something simple Paul.

Now on to a more worrying topic [:eek:] How does Mikie know what a Jean Michele Jarre video looks like [:'(]
 
Thanks Paul. Picked the car up this morning and made it the 10 miles or so back home without incident (seems less prone to doing it's thing when cold). Is at the garage now being looked at. Will post the details when all becomes clear what the prob is for future reference.
 
ORIGINAL: Fen

And if the lead happens to be bad with failing insulation causing the misfire? I've seen a mate get an HT shock from an old Escort, a 944T can only pack more of a kick.
Click to expand...

I did it on an Escort myself, and you certainly know about it. I wouldn't pull the leads now on the strength of that experience. There are of course insulated off set tongs for specifically for pulling plug leads. If it wasn't an issue to do it by hand, why would they make such things?
 
Car back home now and thanks to the guys at SPC for looking at the car at short notice with one of their 2 mechanics off sick. Fortunately(?) it broke down on the road test and it transpires that there was a loose connection on the air flow meter. Not counting my chickens though and will see how things pan out over the next few days. Hopefully, end of thread...
 
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