2005 Gs300 Mk3 Misfire

benlamb · August 2, 2015

Hi all

got an 05 GS300 (MK3) 124,000. plugs and coils were changed at 118,000, at the time one coil failed and was replaced by lexus (before i owned it).

Intended to go to the shop today, got to the junction at the end of the road went to pull out and began to misfire, engine was warm. no warning lights came on.

Pulled over as soon as i could, turned off and back on hoping to clear it, still there. turned round to head home, still no warning lights.

Got about a mile towards home and then the VSC and engine management light came on, but only between 1500-2500RPM.

Managed to coax it home, checked the basics (oil water petrol), got the engine cover off to check all the connections to the coils and plugs. Also checked all the fuses to the EFI, ING and INJ points. all seem fine.

Having looked through the forums can only find VSC light issues but with no mention of misfires, anybody have any idea what could cause any of this? half expecting failed coil pack or injector.

On another point in the top fuse box by the Battery i noticed that all the ABS fuses were not were they should be, looks like they have never been there, any clues?

KR

Ben

ColinBarber · August 2, 2015

Why have all the coils been changed? Were genuine parts used?

Do you have access to a fault code reader, it would be useful to know what error codes have been stored.

Given that the parts have been replaced recently there could be an early life failure of a part or something unrelated like an injector. If an error code indicates a particular cylinder then moving the plug and coil pack would help diagnose the issue - if they are at fault the error should move to the new cylinder.

benlamb · August 3, 2015

Coils and plugs have a service life of 120,000 so they were changed as part of service, with genuine parts.

At the garage now, should find out this soon whats up.

thought process is starting to go towards injector as it seems to be more of an issue under load.

ColinBarber · August 3, 2015

Toyota coils packs don't have a service schedule against them. Plugs do because they can wear down and the electrodes can break off, damaging the engine. Coil packs can fail but don't cause damage and unlike cheap German parts don't routinely fail after a period of time.

Hopefully it will be easily fixed. An injector would certain cause the issues you are experiencing.

benlamb · August 3, 2015

UPDATE;

Just spoke to my garage, fault codes showing coil 1 & 2. But part and parcel is changing all the plugs at the same time, for warranty purposes.

Having a flush, oil and filter at the same time. Looking like £350 all in. Which ain't the end of the world.

Thanks for the help.

ColinBarber · August 3, 2015

Well two coils don't fail at the same time. It's possible for one fault to trigger two cylinders, or even more likely an injector. We see this so many times, people are charged for multiple coil packs when it isn't necessary - people just reading error codes and assuming that gives you 100% accurate information; the error code is there to give you a starting point to diagnose the fault. :(

Let's hope you will be error free now.