ColW

Focus mk3 doesn't run as smooth as it did

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Hi All.

My 2011 mk3 1.6 ti-vct doesn't seem to be running quite as smooth as it used to.

I have just over 55000 miles on the clock. It gets serviced by a Ford main dealer and was last serviced a few months ago. It had new plugs last year and I had the pcm update installed then which made it feel like a new car.

For the last couple of weeks it has been feeling like it stutters a bit accelerating from low revs, especially after slowing right down for traffic and then pulling away again before stopping. I have checked for any error codes in forscan but nothing showing.

I suspected the ignition coil pack and bought a new one which did improve the stuttering but it hasn't gone completely.

Does anyone have any ideas on what I can check? I had a look in forscan but don't know what to look for specifically.

 

Thanks

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Check for any splits or softness on the crankshaft breather pipe it's just behind the intake.

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Ok thanks, I will have a look tomorrow if it isn't pouring down all day.

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Ok I had a look earlier and it looks fine. No softness anywhere and no splits visible.

Does anybody have any ideas what else I can check?

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After a bit of researching I had a little run on local roads with traffic about earlier today while forscan was running on my mobile.

I checked long term and short term fuel trim all seemed to be fine, all below +/- 10. I monitored the cylinder timings and checked for misfire.

I got around 4 misfires over a couple of miles on various cylinders and on checking the total misfires I have over 15000 which I guess is from new.

My next thought is just get a set of new spark plugs and see if it improves things. I don't know what brand plugs were fitted last year but I would have thought they would still be ok.

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I had a similar issue with mine not long back, it was only a single cylinder though and was a bad rocker cover gasket so I had oil leaking onto the spark plug. Has your MPG gone down?

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On 6/17/2019 at 8:38 PM, ColW said:

I got around 4 misfires over a couple of miles on various cylinders

That stacks up with the stuttering when pulling away at low rpm. Opening up a bit from low RPM will give max. pressure in the inlet manifold, so max compression pressure. The voltage needed to make a good spark goes up with the compression pressure, so any problems with plugs, leads or coil pack will cause misfires.

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I got a new set of plugs and mine seems to be running fine again. My mpg seems better but I'm off work for 2 weeks now so won't know fully until I'm back to my normal daily driving routine.

The motorcraft plugs I took out that had been fitted last year looked to be gapped high. I haven't measured the gap but from reading about plug choices people were saying 1mm or 1.3mm and these looked higher.

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Just an update since I'm back off my holidays.

I've been driving my car for the last few days with none of the stuttering/sluggishness problems occurring. My mpg has gone up quite a bit with mixed roads, some motorway and early morning traffic I'm averaging over 38 mpg whereas previously I was lucky to get 35 mpg.

I was surprised the motorcraft plugs fitted last year only lasted around 12000 miles but I'm happy with the Bosch Super 4 plugs I fitted. I read the reviews and I know they get mixed reviews but they are working fine for me so far.

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I have noticed mine loves hot weather and then drives beautifully, between 10 to 20C its pretty nasty, yet above 25 it loves it.... very strange 

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