2001 t4 S40 power/turbo loss?

[afzalmj]

Hi

Have a very strange problem, which I think may be related to low idle (it is triggered by low idle).

Start the the car, drives fine, turbo kicks in normally. However, once FULLY warm and if left to idle for 3 mins, and then take off again, the turbo no longer functions. Its as if the ECU has restricted the power (flat acceleration). Sometimes this happens whilst driving too (I assume if the revs get low enough over a longer period of time, it is the same problem).

The interesting thing is if I turn the car off and then on IMMEDIATELY when this happens, the problem goes away and I get normal boost back. But then it will happen again if left to idle for 3 mins or randomly whilst driving. This leads me to believe the fault is electrical, and not mechanical, as the act of turning it off/on straight away seems to 'reset' it.

I also did a little test. I pulled over when the car was warm, and put my foot on the gas so it was idling over 1000RPM. I did that for 3 mins and then took off. Turbo was fine! No power loss. So leads me to believe something happening due to too low idle.

This problem is really annoying me!! I've replaced the MAF too, no luck . Any ideas?

I'm based near London so anyone in South east can help out?

Thanks,
Afzal