Noticed lately that the car has lost a lot of it's performance. That kick that the V6 gives at 4k rpm has now gone.
Engine still sounds great, but tailpipe soots up quite heavily. Also pops very very slightly a bit sometimes on throttle release. Can sometimes be a bit lumpy on idle when warm and takes more engine turns to start when warm. When it does start when warm it's a bit spluttery.
I am guessing o2 sensor for this one as it's temp related. Feels like the engine is on choke all the time as originally when on choke, it felt the same and once warm, had full performance. But as I say now, it has 'choke' performance all the time..
CTS is only a year old, so could it be that also?
No ECU light.