Engine lacks power when hot

[flybobbie]

Colleagues car went in for its last warranty check before it ends. Car a 2011 23i and 10k miles.
When she picked it up, commented the interior was very hot and on the way home, then a problem the car had in the summer re-occurred.
When you put your foot down on the accelerator the power fades. Would struggle to pull away in second.

Her normal journey to work only 3 miles, the car never gets to high temperature.
Soon as summer arrived and a motorway journey the problem occurs.
BMW obviously never cured the problem when they had it in during the summer.

I suspect a combination of being sat in traffic before she arrived plus the dealer probably ran the car to check the fans and cooling system brought the problem out again.
This would explain the high cabin temperature. No check lights on.
The dealer wouldn't see the problem as they probably don't drive the car.

She says they are going to pick it up next week to have a look. I said take the car in person, sit on car park for fifteen minutes engine running then get them to look at it.
If she's there she can put a bit of pressure on them by waiting for them to solve the problem.
This is interesting;
http://ngkntk.co.uk/index.php/technical ... a-sensors/

Anyone experienced this problem. Would Lambda sensor faults show on the check lights for instance. I say Lambda, as the only thing I can think of that would break down at high temperature.

Another strange thing, car doesn't show up on a vin checker?

[TONYMOR]

I've a 2011 2.31 can't say I recognise any of these problems .
As regards power I do too many short journeys and don't use the car probrably enough but I add redex to the fuel as a way to help Keep the injectors clean and albeit use supermarket fuels but occasionally use shell v power . It does help .
Has she tried contacting another BMW dealer to acquire a second opinion ?.

[flybobbie]

This cars been a bit of a lemon, to the point she's quite prepared to push it over a cliff.
First the tail light saga. Then the roof was barely used before it failed and required a quite extensive repair.
They tried to fix the lack of engine power last year by replacing the Vanos solenoids.
Then the Vanos bolt call back (which they said was probably cause of lack of power)
Now the power loss again.

[flybobbie]

Well car fixed.
Two Lamda sensors replaced.
Which two not sure as there are four.
Would suspect the two pre the catalysts as these probably get hotter.
At least they are easy to get at.

I will store that one for future reference.

[TONYMOR]

Hope that does it and stays like it .
Good luck and hope it continues .