Hi guys, I have been having an issue with my focus st 2009.
When I drive the car fast ie over 5000rpm then the engine management light flashes and the car starts to misfire. But if I pull over and switch the engine off and start it again the problem is gone. I have also check fault codes with bluefin which says no dtc found. It doesn't do it all the time it's only done it once about 6 months ago and then it done it again tonight (being a bit naughty racing a mk2 rs which I was surprised I actually beat). I fitted rs plug thinking it was spark blowout but still no change. also i dont know if this has anything to do with it but the 2 times it has done it i have been going up hills. Ps the car is at stage 3

Thanks!

 

Did you check the condition of the plugs when you took em out. Could be a duff injector or coil.

 

Yes Plugs and everything else looked visually ok. It was just to see if anyone has had similar problem as it has only done it twice but it is annoying having to pull over and restart the engine. I will possibly need to get it on a rolling road and check it there. Thanks!

 

odd one that is. Dyno seems like a fair idea. Make sure the AFR's get monitored though

 

I've never been to a dyno before, can they monitor the AFR with there equipment or will I have to by a wideband senser?

 

If they can't mate, get back in the car and drive away. It's an absolute minimum requirement for a Dyno and should also include full OBD data stream monitoring as standard as well if its a decent one as your focus may need that to find the fault.

 

As above.

They should be able to access if through the odb. But they could also just out a probe up the exhaust

 

Thanks for the speedy reply guys!

I'll get it booked in for a session soon to try and find the fault.

1 last question when I was in halfords getting oil and filters they stocked a fuel filter for the focus st post 2008 but I was under the impression that it was fitted with a lifetime filter. Did ford fit a changeable filter on the facelift cars? Because I've never change it

 

Going into halfords will be your first problem :P

Yep it's a lifetime filter, and is located in the tank.

 

Thank for the help lads, much appreciated!

 

Ok guys little updated,

Cars booked in at the dyno for next week, but I think the problem is getting worse. Was driving last night and it started to misfire very bad with the engine under heavy load ie going up hill on full boost. It misfired enough to put the mil light on constant so I plug the bluefin in and it show fault code p0300 which is (random misfire detected). So will keep you posted on any developments!

 

How did you get on I have the exact problem!

 

I removed the plugs and found that number 2 was burned ( electrode was a sort of pitted grey colour, looks a lot like a piece of metal after it has just been sandblasted ) and number 5 plug the electrode was completely burned away.

The plugs where only fitted a few months previous so I was a bit worried.

So I put some new plugs in it and took it to the dyno and got it check out and the operator couldn't fault it.

The only thing he though was causing it was that as the car was running higher than standard boost the standard ford plugs where over heating and to fit a colder plug so I've been running denso iridium plugs for a few weeks now and it seems to be ok.

I will keep an eye on it but so far so good!