1999 F-350, 7.3 Diesel, 6 speed.
I am replacing the exhaust back pressure tube and sensor. The original tube is both totally clogged but also has a hole in it rendering it useless.

I noticed that the truck has been surging a bit at about 1400 RPM.
What does this tube and sensor do?
Thank you.
Eric

 

The sensor measures the pressure in the RH exhaust manifold. It is used with a back pressure regulator. The back pressure is controlled by the PCM to provide more heat to the coolant for cab heating when ambient temp is below 45 degrees F,and engine oil temp is below 167 degrees F during low speed or low load.

 

Hanky, thank you. Would a clogged tube cause a surging in the engine at about 1500 RPM?

 

The tube and sensor have been replaced. I also ensured that the fitting on the exhaust manifold was cleaned out (It too was totally clogged)
Engine still surges under light load and the surging has become a bit worse.
What is going on?
Thank you.
Eric