9400i intermittent rough idle, excessive black smoke and fault code.

Friend of mine has 07 9400i with ISX Cummins. Intermittent rough idle when warn engine light is off. Smooths out when light comes on. Heavy black smoke, especially under load. Fault code is 128:F02 PID131_A. I checked the fault code links, but this code wasnt listed. Anyone know what this code is?

 

Yeah, he just went to a T/A and had it diagnosed. They told him the same thing. I will call him and tell him bout the thread on here. Thanks!

 

Update: He replaced one the exhaust sensors that was on the right front top side of the engine. It didnt fix it. So he found another sensor that was in the exhaust manifold. both sensors looked about the same, only the connector was a little different. Anyway, he took the sensor out of the exhaust manifold and cleaned the soot off of it, and put it back in. Viola, no more check engine light. He's still getting more black smoke than normal though. Says it still has good power.

 

Asked him again. He said the one he cleaned was actually in the intake manifold and the one he replaced was in the cylinder head. He said the one he replaced, dealer called it an exhaust pressure sensor.
Been a couple days and no more more engine codes. And its smoking some but not as bad. Fuel mileage back up to bout 6.1. It was down under 5 before he cleaned the sensor.