A4 b7 p0401

[Andreiul]

Hi guys, i have a 2.0tdi BRE A4 140 hp which has been fine for the past 3 years , but one day when a left home i noticed it suddenly lost power and i heard a chattering sound under the hood. As i was driving i noticed power would come back and then disappear again and would knock off my cruise control. The fault where P0401 and P0403 EGR sensor and cooling system sensor so i bought a new EGR (the old one had the plastic wheel broken ). The cooling sensor error is gone but the car is still not drivable. Same loss of power but now when i get some back , either i have full power or the engine is choking, with that chattering sound very loud (2 out of 5 time its choking). Today i took the cooling system apart to clean it but there was nothing there to clean.I had a mechanic checking the power on the cables and everything is ok.
What else can bring up the insufficient plow error if the EGR is new and all the pipes are cleaned?
Thanks.

[Rob69]

Has it got the V157 intake throttle flap upstream ( air flow) of the EGR valve? I've had to replace a few of these and they haven't always logged a fault code.

[Andreiul]

Yes it does, but it is working.