*Manual 1998 Dodge Ram 2500 3/4 ton 4WD 5.9L Turbo Diesel OHV 6cyl 24V*

Greetings!

On my 1998 Dodge Ram 2500 I am having issues with a long hard start. The VP44 was replaced in April 2022. I had no issues until around October of this past year. It began to hard start on me at that time, and approximately 1-2 weeks later my Throttle Position Sensor began throwing a code and giving me issues in stop and go traffic. One discovery I made was that the truck does not give me issues if I start it while it is facing downhill. However, if I start it on level ground, or with the nose facing uphill then it begins to give me issues. I do not believe it is the VP44 as the VP44 does engage when I turn the key. It is almost like there is some sort of air in the fuel lines. My question is 1. Could the Throttle Position Sensor cause this issue? and 2. Are there any other things I should look at or consider? From what I have researched I am hearing I should look at the ECM, and look for leaks at the heads. This is my first diesel truck so I appreciate any guidance.

Thank you!
-Dan