We are struggling for a long time with our alfa 155 q4 turbo.
It was good, 4 or 5 years ago, we took it for a drive (also with squadra chip), on francorchamps (spa italia days), after that weekend the engine began to hesitate.
Slow driving was ok, but from the moment the engine needs to produce torque, it hesitates.
The issue gets worse when you are driving longer, (but in the beginning it was not so bad).
We checked everything, replaced pressure sensor, air temp sensor, tps sensor, lambda sensor, knock sensor, crankshaft sensor.
We also noticed one cam was being worn, replaced wiht new camshafts, but still problem was there. I measured with my lambdasonde, egt, rpm, pressure, but couldn't find a cause of the problem.
Now the problem is really worse, you drive 1km, cold or warm engine, the first meters it looks that everything is ok, but after a few min driving, it gets worse, so worse it's difficult to get back home. Even at idle it begins to turn rough. Sometimes you start the engine it's ok, other time it's not ok.
Coils we also replaced, also the ignition modules, no solution.
But this weekend I found that when the car is rough idling, if I measure with a strobe on every sparkplug wire, there is not a good signal at some of them.
So now I know it must be something with ignition.
Coils I allready ordered, but does someone know where to buy the ignition modules? can't find them here.
If both of them are new, then I hope it's solved.
Because if I switch between the two ignition modules with the connectors the problem goes to the other cylinders. (or there must be a bad cable).
Hopefully someone can help us further with this