About two weeks ago, I bought my first diesel
It's an 06 F250 with 95,000 miles on it.
While test driving it, I notices that when idling after the engine was warmed up, the RPM would start surging between 500 - 1000 RPM. Other than that the truck was in great shape. I took the truck to a mechanic who told me the problem was due to the fact that the fuel filter needed to be changed.
Last week, I changed both the fuel filter and oil and the truck still would occasionally surge once the engine was warmed up.
Today when driving, I was idling at a stop light and the engine started surging again. However, once the light turned green, I pressed on the accelerator, and the truck continued to idle. I pressed the accelerator to the floor and nothing happened. The truck just idled through the intersection... NOT FUN. I turned off onto a side street, and the truck stalled out, and it took a lot of cranking before it would start again.
Being that I've never worked on diesels before, I have no clue where to start. searching for the problem. No codes come up.
What should I check? FCIM? Accelerator pedal?