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Mike, Ford Technician
Category: Ford
Satisfied Customers: 39198
Experience:  Tech Expert
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focus c max 2004 1.8 duratec mis fire. recently I broke down,

Customer Question

focus c max 2004 1.8 duratec mis fire.
recently I broke down, with a mis fire. The AA attended and diagnosed a suspected valve issue on cylinder 2.
further investigation found a burnt out exhaust valve in no 2 cylinder. This has been replaced and the engine put back together. the car had a slight mis fire, which has become more noticable at between 1000 - 2000rpm. The engine management light is either lit all the time or flashes at speeds above 35/40 mph.
Can anyone offer any advice as to what could be casuing this?
Submitted: 5 years ago.
Category: Ford
Expert:  Mike replied 5 years ago.
Hello and Welcome to justanswer...

My name is MIKE - Im happy to help you with this...

Have you had any plug in / diagnostic tests done at all - ? If so, what where the results of that ?

Plus - please give me the vehilces Full reg number also -

Rgds- MIKE....................................
Customer: replied 5 years ago.


hi Mike,

Only had the inital diagnostic test which showed fault on no 2 cylinder.

Vehicle reg is DN54 PZB



Expert:  Mike replied 5 years ago.
Hi there Mark -

Apologies, your reply came after I had gone for the eve..

Ok well there are a couple of possibilities as to the cause of this Mark..

The good news is that the EML - Engine management system fault light is on / flashing - so that means the Pcm ( computer) will be logging relevant fault codes for the fault you have now - so a plug in diagnostic will be needed to retrieve those fault codes - and then go from there -

Before that, basic checks should be made as to the integrity of connections to the ignition coils - and also importantly, engine earth connections and sensors... and too - engine vacuum pipes for condition / connection. After such a rebuild its not uncommon to get a bad one of the above -any one of which can cause what you have... so those basic checks should be done first... then the code test.

Then go as directed by the code - but I'll just mention too , other possibilities... they are that you still have a problem re the valves replaced... I have known of cases where by the new valve/s have not been fitted correctly - insufficiently ground in to get a gas tight a compression test done cold and hot would find that if thats the case... or, the valve / specifically the hydraulic lifter can be sticking in use in the aperture in the head... again - compression testing is needed for that..

Other , is the possibility of faulty spark plug or ignition coil - while basic, often missed , so bear that in mind too..

Lastly you can have a Pcm unit fault - but I doubt that to be honest at least at this stage. Its very likely a follow on from the major work thats been done as above -so if you / they work through as above, you will get this sorted one way or the other - let me know how you go on.

Let me know if you need anything more on this at all -

Meantime -- Please click on the OK rating to Excellent ratings service for me now, Thank you for that... and you can get back to me anytime if you need / wish..

Best Rgds, MIKE.

Please note, you are rating the content of my "answer" - my help to you - not the "system" which can experience delays etc which are not under my personal control -or delays caused by "time -off" which we all have on occasion - Thank you.