Help! From check engine light to fouled plugs back to check engine + plugs refouling

[FRSBRZGT86FAN]

Originally Posted by steve99

The cam actuator operation/position is monitored pretty well you would expect codes related to cam actuators ect if that were the case.

It's pretty mind boggling so many sensors and issues at least 4 or 5 off the top of my head could cause a "AFR imbalance", it's a pretty broad code, it makes sense the mechanics are having an issue with it then, or they are probably incompetent.

[steve99]

Originally Posted by FRSBRZGT86FAN

It's pretty mind boggling so many sensors and issues at least 4 or 5 off the top of my head could cause a "AFR imbalance", it's a pretty broad code, it makes sense the mechanics are having an issue with it then, or they are probably incompetent.

Yeah maybe
but if its running pig rich you should smell it in exhaust fumes
then you need to find why its running rich. not just change the plugs.

although some people do weird stuff, guy over here decided he would run E85 on a stock petrol tune, cause he heard that you get more power ,then wonders why it running crap.

did not let on he put in E85 so your thinking wtf is wrong untill you smell the exhaust and it tweaks.

[Spartarus]

Originally Posted by FRSBRZGT86FAN

Has anyone thought of unusual valvetrain issues?

Yes. But it it doesn't fit well for your problem...

We still don't have enough information.
@steve99 was correct in saying if there's a bad component in the valvetrain, you will likely have a related code...

If the variable cam actuators are anywhere in their mechanical range stuck or uncommon dedicated you shouldn't get serious afr imbalance sufficient to fold the plugs, it'll just run and idle like sh*t.

Little while ago a guy broke a valve spring. That won't throw a valve train related code, but you will have rough idling, afr issues, and random/multiple cylinder misfires.

Still want to know which plugs are fouling...

Theoretically, if you had a bad coil, the associated plug would foul, but the ECU on this car uses a crank speed variation algorithm to determine misfire, and you would have at least 1 misfire code.