Power Loss after running 50km

[AxelF]

Hi guys,
i am new to this forum, trying to buy a Clio I 16v with a Megane F7R engine.

The engine works good (was overhauled recently), ECU has been updated to work with new engine.
Only if it drives for longer time (at least 50km) it starts to slow down and drive only 80 km/h max. No error code in ECU.
Did anyone had such problem before?
Thanks
Christian

 

[da rok]

Are the revs limiting at 3000 rpm? Thats the normal limp mode rpm, if the computer has been re mapped for the new engine then there may be a problem there. Could also be a sensor breaking down that may be messing around with the computer

 

[AxelF]

I have to be precise: its not like a limiter, the engine behaves like it gets not enough fuel.

ECU, wiring and ignition is from Clio, engine itself from Megane.

 

[da rok]

Try re mapping it, odd that it happens after a certain distance though.