Another misfiring Ford Focus

I've got a 1999 Ford Focus 1.6 Zetec with 103,000 miles of the clock that has recently developed an intermittent misfiring problem.
The misfire usually occurs during acceleration in 4th or 5th gear or
when accelerating hard in lower gears. Most of the time the engine idles fine however on two occasions the misfiring has been pretty severe and the engine has stalled whilst idling. So far, I've changed the plugs, leads, coil and fuel filter with no luck. I've also had my local garage run it through diagnostics that didn't find any fault either (although it apparently was idling fine throughout - typical!).
The car has been serviced regularly and the 103,000 miles are almost all easy motorway miles so I was expecting a fair bit more life out of it.
I've read other posts in various forums that describe misfiring problems but either the symptoms are different or I have already tried the suggested cures.
Has anyone got any more ideas as I'm running out fast!
Cheers,
Andrew
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

We don't have that motor over here so I'm just reacting to what you say, but you don't mention fuel pump. Since there are no codes, I'd concentrate on fuel delivery, and the pump is suspect number one. Over here, Ford has offered owners of 2000-2001 Foci a 10-year warrantee extension.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If the leads have done more than about 40k miles, change them, use Genuine Ford only. If the plugs have done the same, change them too. Wipe the surface of the coil pack with a solvent soaked rag, and ensure the new leads make good electrical connection.
If that doesnt cure it, then you need to investigate further.
Tim..
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I had the same problem some years ago with my old 1.8 escort it was just bad petrol.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@og.ge.com (Andrew Wilde) wrote:

My old Mitsubishi idled rough. When I took off the egr valve to troubleshoot for a smog test, I found a huge amount of Carbon build up. I squirted water down the intake manifold using a windex bottle. I went through several bottles, and it was much better after that. I guess you can get hot spots with the carbon that can lead to early ignition of the gas. Just a wild guess...
Brian
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Cheers for the suggestions. Since I posted the message, I've tried simply adding some fuel flush. The local garage were pretty good and they replaced the new leads and coil that they had fitted with my old ones which they'd kept - obviously charged me about 50 in labour but generous none-the-less. The fuel filter had made no difference at all, but the fuel flush may have done. It didn't misfire for about 3 days but the problem was back this morning after I filled up the fuel tank. I haven't suspected the fuel pump as yet as I always thought that it either worked or it didn't.
I'm going to continue with a bit more fuel flush and keep my fingers crossed.
Thanks again,
Andrew
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

--
Paul Giverin

British Jet Engine Website http://www.britjet.co.uk
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

A blocked fuel filter will not cause a misfire. It will however cause stuttering and stumbling at wide throttle openings- such as when over taking, or going up hill- fuel flow is restricted and cant keep up with demand.
It still sounds like you have an ignition problem to me.
Can you give another description of when the car will misfire, hot, cold, low speed, high speed, throttle opening, can you induce it on demand..? When were the plugs last changed??
Tim..
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
PS,
is it a regular single cylinder misfire, or much more violent spluttering? There is a modded wiring loom for the CHT sensor between the plugs which is part of a TSB more for erratic temp gauge and fuelling problems, but it also addresses a misfiring problem where leaking HT voltage tracks up the wiring to the ECU which causes it to momentarily shut down.
This will present itself as a violent misfire, you might even notice the dash gauges begin to drop to zero, or freeze when its doing so.
It is important that the HT leads are correctly clipped, seated on the plugs properly and not in contact with the CHT wiring too.
Hope this helps alittle...
Tim..
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I fill the car up from all over the place so unfortunately, it's not a supplier problem!
I wouldn't say that the misfire is severe. It occurs both when the car is cold or warmed up and in all sorts of weather (we're getting a good variation in England at the moment!). The only common factor is that the misfire occurs during hard acceleration, usually in forth or fifth gear and usually when going up a hill. When it's bad it happens in lower gears and on the flat. The engine has only idled badly once and the fuel flush seems to have cleared that up. The engine also seems to have lost power in the higher gears, even when it's not misfiring.
Too me, everything is pointing towards fuel supply, but I'm no expert. What else could cause fuel starvation? Vacuum in the tank, blockage other than filter, dodgy pump?
I'm sure I'll get there in the end,
Cheers,
Andrew
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I had a GTI a few years back that did the same thing, intermittently. Turned out to be a couple clogged injectors--probably from crap fuel from all over Florida. Running injector cleaner through them is only a temp fix--they need to be removed and cleaned. I'll bet that will fix your problem and it shouldn't be too expensive.
--
Raider Rick

"Just drive, baby"
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It doesn't state that it covers 1999, but...
http://www.autosafety.org/article.php?did 8&scid7
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.