TurboII2NV

I dont usually post problems here, but I really cant figure this one out and maybe one of u can give me a leading direction.

My Turbo II 87, is running good all the way untill driving about 10min in operating temperature. Than it starts giving a fuel cut around 4000rpm

There are no modifications to the car.

I checked the Thermo sensor, coolant sensor, boost sensor, MAF sensor, variable resistor, and resistor pack
all seems in good specs.

And one more thing my idle never drops below 1200rpm

If u guys have any answers let me know
thanks in advance

Parastie

Have you checked grounds? It's the only the only thing i can think of.