I have a mk111 ecoboost 1.5 petrol and was thinking of putting a k&n e2993 air filter in. I read a review on Amazon where someone with a Kuga bought one and had trouble with it going into limp mode, changed back to normal filter and car was fine. I don't want to waste money if it could happen on my focus. Anyone had similar trouble please?

I have had limp from a K&N, but I dont blame the filter, I blame myself for just throwing it in dry and not cleaning it as I should have before I swapped it over. 

I've got the e9289 and have had the same one for 3 cars now, it's in my diesel ST and although it's been brilliant in the other two petrol cars, I've had a bit of beef with limp on this one which was down to a cloggy MAF sensor in the airbox. It wasn't clean anyway which I know, and for the ~6 months I had it on the ST I hadn't cleaned it before installing so it was dry and not efficient as a filter.. I imagine anyone with limp mode from a filter swap is very likely the same thing - it's a cheap replacement part if needed or a quick clean to resolve if you wanted to go that route.

Sure the K&N filter isn't going to stop as much as a paper, but in my experience it hasn't really been an issue if you just keep it clean.

For me, I know my sensor was dirty, and I accept that dusty bits getting in probably didn't help, but looking at the pipework etc when I've had it all off theres always been nothing lining the insides on the ST where on my 08 Focus 1.6 the fit wasn't quite perfect and I could get a tiny amount of dust from the inside of the intake if I run my finger around it, but a zip tie fixed that.. (Pipe was worn to hell anyway from someone before me faffing with adapters or something..)

The main takeaway is to just make sure you've got it installed correctly and keep it clean/oiled, but not over oiled. You should be fine!

 

Thanks for that