Subaru Impreza 2011 2.5L WRX STi shaking on idle?!

[Gachette]

Hi all, first post so dont shoot me...my subaru is rocking quite violently on idle...just today took it out for a drive with the missus to do some shopping (I told her I didn't want to go haha And the car obviously agrees) on the way back the engine management light starting flashing and the engine started shaking on idle. Cruise control light came on...and i can't change the driving mode its stuck on Sports..
Any ideas? Was driving smooth and I didn't run it today just cruising around...floored it once or twice but nothing major, Im in London so no chance of that middle of day.
Saw an old post on here but it was from years ago...mechanic is off and I dont trust anyone else to touch it, had it serviced just over 2 weeks ago when i bought it...literally made it home by the skin of my teeth.

Edited by Gachette on Tuesday 26th December 20:57

[MDMA .]

Sounds like it's misfiring. You really need to see what code it's throwing up and take it from there.

[Gachette]

Well got down to my mechanic today...4th cylinder misfiring...told just to call me when its done 🤔🤔 . Thanks MDMA for the quick reply. Any chance the seller knew this was gonna pop up or is this something that just randomly happens? Bought from a dealership through advertisement on here. Travelled the length of England to buy this beauty...

[R12many]

Simple cause could be spark plug, coil pack or injector. Worst case is the dreaded ring land failure! Be prepared for the worst as cylinder 4 is the usual culprit.

[MDMA .]

R12many said:

Simple cause could be spark plug, coil pack or injector. Worst case is the dreaded ring land failure! Be prepared for the worst as cylinder 4 is the usual culprit.

Yes, worse case it could be. What was the code? Are you running on V Power? Has the mechanic just cleared it and said be on your way?

[Gachette]

Hi nah he said leave it with him as he has a ton of stuff to get through first day back and all..he'll give me a call tonight and I'll ask him the code. It's p301-p304 for cylinders right? God I hope it aint disasterous...so this can just pop up no warning? That's whats bugging me most......would the cruise control, sports mode be stuck if this is problem...or just need resetting ecu after whatever work needs doing etc

[R12many]

Cruise control disabled light is normal when you have the engine management light on. If it is ring land failure then the bill will probably be a couple grand to repair but you may as well go forged.

[Gachette]

Yea it'll be fixed whatever it costs. Just fingers crossed it aint as bad as worst case scenario :-(

[nw942]

If you've just bought it you have some rights: https://www.moneyadviceservice.org.uk/en/articles/...

Maybe get your mechanic to diagnose it and then see what the dealer says?

[Gachette]

That's not loading for me but I'll have a look online...mechanic says it need new coil pack so i don't think dealer would have none would they? Hopefully be done by end of week so I'm stuck driving my missus corsa In the meantime

[MDMA .]

Cheap easy fix then. Genuine ones only around £70 mark.

https://www.importcarparts.co.uk/parts-info?id=482...

[Konan]

You get some really odd forces from a misfire on a boxer engine. It's not a wobble you'd miss in a hurry!

My coil pack on the way out always started to show on a hot start in damp weather.

[nw942]

nw942 said:

If you've just bought it you have some rights: https://www.moneyadviceservice.org.uk/en/articles/...

Maybe get your mechanic to diagnose it and then see what the dealer says?

Sorry - there was a space on the end of the URL.

https://www.moneyadviceservice.org.uk/en/articles/...

If you only bought it 2 weeks ago the supplying dealer may well pay for the coil pack.