Audi V8 4,2 aut -92 running att even speed at above 90kmh makes a very short interruption and somtimes it feels as an smal acceleration ,just after, just like when lock-up goes in. It all takes perhaps one second and nothing shows on instuments and can hapen aprox. once to ten times for 10km ride,
It´s not the waveformed run as when lambda is out of order and it´s not AC compressor engaging
Dont know if it is lockup that goes out and in or engine that stops and starts
Lockup works as normaly . Goes in at 90 and out in perhaps 50-80 depending on footwork. All other gearchanges are so soft that I can´t feel them.
Engine also runs great 1,2 to 1,3 liters / 10km
No faultcodes at engine but at autotrans there is "no brake switch signal " error . This error is there even if I press brake pedal. This error has been there before this problem started.
I read somwhere that brake signal is used to get lock-up out when brake is pressed and ABS i indikating that some wheel not is rotating. This could bee what happens but how to verify this and fault finding ?

Bengt