Random loss of power

[TSPowell]

My buddy just purchased an 04. 5 auto with 120,000 miles. The truck is experiencing a pretty bad loss of power randomly. It usually occurs when its cold and the truck has sit for 2 days. We are located in Colorado and when trying to climb hills it wont go over 1700 rpm, and 40 mph. He says if he gives it more fuel it smokes a little more. I figured its probably a fuel filter, fuel pump, rail relief valve, or FCA issue. I just cant figure out why it happens when its cold. ANY IDEAS?? Im going to try and figure out the fuel pressure soon. I also have a fitting from GDP to see if the rail relief valve is leaking.

 

[CToney]

Start with filters, check for codes, and make sure you have enough fuel flow.

 

[TSPowell]

I forgot to add that there are no codes associated with this problem

 

[cerberusiam]

Add APPS to the potential trouble spots to check. How did you check for codes? Some will not set a CEL and you will need a reader capable of getting them out correctly.

 

[TSPowell]

How did you check for codes? Some will not set a CEL and you will need a reader capable of getting them out correctly.

I used the key ingnition method to check for codes.

 

[cerberusiam]

I used the key ingnition method to check for codes.

You could have codes that will pin point the problem that the key trick won't read. Need a regular scan tool or code reader to check for sure.

 

[p-Bar]

How about boost ? any gauges?

 

[TSPowell]

Some good news... the fuel filter was changed yesterday and since then no loss of power has been noted. He said it was very black. The weather hasn't been too cold yet so we'll see if it continues to act up. I also adjusted the valve lash today.

 

[p-Bar]

well the filter media used seems to turn black as soon as the diesel hits it .