Factory ecu - does it have a warmup function?
 

As above. Does the ecu limit power until the engine is up to operating temperature?

I have a S7 with a REDOM ecu and power is down unless I thrash it for a minute or so or pull over and let heat soak into the engine while idleing, then it makes full power, until I back of for a while allowing temps to drop and its back to low power.

I'm thinking either the thermostats stuck open a little or the water temp sensor is on its way out. Ofcourse if the ecu doesnt have this function built into it I'm back to square one.

Can anyone confirm this?

If it does have that function it's the first time I ever heard about it. Mine certainly never behaved like that.
What's a REDOM ecu?

well isn't the double throttle function somewhat the same thing?

The ecu will run pretty rich at idle, foudble throttle will limit your boost, AWS will keep you at 3k for a while... all this will limit your power

not trying to come off like an ass or anything, but out of curiosity how will the AWS limit the usable power? I thought it just kept it at 3k for a little bit to warmup the car, but is totally cancelable by just blipping the throttle for a second?

The double throttle plates will not open until after 176F water temps, limiting you to about 5 psi or so (this is stock ecu controlled). If your water thermosensor is reading low for some reason, that could be a cause.

This would be easy to diagnose if you had a boost gauge...

Actually it limits you to 8psi. Well atleast that's what my car gets.

Bingo! Thanks mate. Boost doesn't seem to be down significantly but its easy to disconnect the double throttle and see if it make a difference.

gotorx7 - REDOM is a sticker RE Amemiya stick to the factory ecu to show they've re-mapped it.

All sorted. Someone had fitted a 65deg thermostat instead of the normal 82deg.
For anyone whos interested, the double throttle isnt the only thing that limits power a low temps, disconnecting it made no difference so I guess the ecu retards the timing or something similar until operating temp is reached.