Hi All
I hope someone may shed some light into what is going on with my 2014 1.2tsi 16v CJZC Polo. 41k miles.
1) When I start the engine from cold - it behaves fine,.... i.e. slightly higher idle for a brief moment, then quickly settles perfectly on +/- 650rpm
2) When I start the engine warm-hot, ....after some journey, ...it also behaves absolutely fine. (same as above)
3) BUT when I start the engine +/- 4hrs after stopping, ...it will start with a higher rpm (approx. 1200) then within the next minute or so, will slowly go down and eventually settle on 650rpm. During this settle-down time the car tends to shake ... and IF I drive it during this time, it sounds throaty.
I believe it must be temp related, because on a hot sunny day, this "goldilocks" hesitation zone is longer, i.e. around 6hrs after stopping,.... and on a very cold day it is shorter, i.e. around 2.5hrs.
Any other time,... earlier or later than this "goldilock" zone causes NO probs. and the car idles perfectly immediately.
Recently my O2 sensor2 died (after cat) so I replaced with the approved Bosch (long cable) and reset the fault codes via (limited) diagnostics - and for some time this hesitation problem seemed to be slightly less, .....but now it's the same as before. I fitted the new after-cat O2 sensor around 2 months ago.
I would like to ask what might be causing this limited starting hesitation... anyone else have or know about this prob ... and what to do ?
Maybe? pre-cat O2 sensor, coolant temp sensor, temp sensor for fuel pressure,.. or something else be the root cause ?
I bought the car new ( in 2014 ) and this issue has only shown itself since needing to start/stop after around 4hrs !! (on a normal day)
Thx in advance for any tips.