M50 strange error

[grave77]

my friends car has sort of hesitation RPM goes 200 - 400 difference while driving. also has rough idle. diagnostic tool came with this error "Ignition Timing Intervention "
the engine is M50 non vanos. pls advice.

thanks all

[632 Regal]

did you check the crank trigger (if it has one)?

[grave77]

well ... if it was faulty I would think that the diagnostic tool would say. but the way it behaves is also periodic. as if the AC is on ... the same way it behaves. but it also affects the torque quite much than only reving the engine up and down.
the car is already at the workshop and they wanted some time to fig out what it is.

I disconnected the MAF to see if it was doing it. but it was still there.

first faults were O2 Sensor and MAF with the Ignition signal Intervention.

after clearing Fault memory only the last one remained.