Quote Originally Posted by 6.5_Diesel View Post
I was wondering if the resistor change could mess up the air to fuel algorithms and how the ECM responds causing the issue. I have read that the computer can be very picky when it comes to maintaining proper air to fuel. What is the stock resistor for a 3/4 ton F VIN engine? Is it still a #4? I remember reading somewhere what it was but I cannot remember.
There is no such thing as a "fuel to air ratio" when talking about a diesel. A diesel should always have an excess of air, with fuel-rate determining engine speed/power/emissions. A turbocharger just allows more fuel to be injected, to make more power.

Most fuel injection pumps use a #5 resistor. The resistor is used to calibrate the fuel-rate of the injection pump. Due to mechanical tolerances, some pumps need a little more help than others, which explains the need for a calibrating resistor. Can't go wrong with a #5.