ford focus misfire then hesitation please read????

[anthony25]

hello i have a ford focus 1.8 zetec petrol 82k miles on the clock which devoloped a slight misfire so changed the plugs leads and coil to no avail so while the car was misfiring popped the bonnet took each electrical plug of the injectors one at a time see if one made no difference and number 2 injector was not working so swapped numbe r2 with number 3 injector i have no misfire now but engine seems to hesitate as i build up speed sort of holding back over 50-60 mph its sweet as a nut i have no engine light on it idles perfectly any ideas scotty thanks,wayne

[TWR]

Have a look under the bonnet at night time without any light in the area & check for Elect Tracking. Check each plug lead connectors.

[tommy.h]

Hi anthony25

suggest you invest in one of the many things such as Redex or Forte injector cleaner.(also cleans your fuel lines).
please don't believe all you may be told about these cleaners some of them really do make a difference.
ask at your local auto shop & see if they can recomend something.

tom

[AlBags]

Do a compresion test next. Hot and dry cranking on starter.
No engine checklight at all?
Lambda probe ok?

[AlBags]

^ (Ford daftly call this a Hego sensor)

[Leoantist]

Had this problem, here's my threads:::



Speedo & ECU - My Story

Jan 2013 - Bought: Ford Focus - 1.4L - Mk. 1 - 2001 - 110k miles.
Right from purchase the speedo would occasionally cut out.
When cut out this effected the ECU.
When speedo cut out car would stutter with its fuel injection because ECU is confused.
When speedo comes back to life, car is fine again until speedo cuts out next time.

Feb 2013 - This speedo starts to cut out every journey + the stuttering.
The fuel injection stuttering starts happening even when speedo hasn't cut out.
At the same time the engine begins over revving itself when car is stationary.
At the same time the engine struggles to accept fuel when putting foot down in gears 1, 2 & 3.
I research the issue, bought and fit a new speed sensor: bit.ly/1125vvW
Speedo ceases to cut out, happy days.
However the fuel injection stuttering/over revving/ engine struggling to accept fuel remains.

Perhaps I left problem for too long: confused ECU has damaged something else? Very common Ford problem. Does anyone know of a solution to the problem?

speedo, ecu, fuel, injection, ford, focus, over, revving, rev, stutter

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Rich watch this space if you get any further problems!

I purchased a cheap throttle position sensor from ebay for £15 (genuine part normally costs £70), fitted it and didn't solve the problem, so moving on.

After some research this is what I have found with regards to the stuttering/fuel starvation/misfiring :::

ecutesting.com :::
This common fault of misfire on two cylinders or complete non start is often caused by the ignition coil pack shorting out on the vehicle - it is very important that the ignition coil pack is replaced at the same time as refitting your ECU after it has been repaired - or your faulty coil pack may damage the repaired ECU. - http://www.ecutesting.com/ford_focus_mondeo_ecu_misfire_.html

EXCELLENT thread from RAC.co.uk on this topic :::
Lots of detail into this very common Focus MK1 98-04 fault here:
- http://www.rac.co.uk/forum/showthread.php?6406-Problem-with-a-Ford-Focus-Misfiring

How I think the problem occurred :::
I believe that when the speed sensor started malfunctioning I continued to drive the car, which may have caused the faulty speed sensor to damage the Ignition Coil Pack which then damaged the ECU.

How I'm going to tackle it now :::
Take out the ECU, read it's part number and send the ECU off for repair/replacement by ecutesting.com for (hopefully) £150.
Purchase new ignition coil pack for £25.

Will let you know how it goes :)