hey yall. first post here. 2004 F250 6.0L

i just did the blue spring upgrade and changed the air filter and about a week later i started noticing a slight misfire at idle and when on the highway between 1500-2000 RPMs. at first it only seemed to happen once at operating temp but now it will happen more often. i can't say that i have ever noticed it when i first crank it in the morning when it is completely cold. it never just runs terrible. just a hiccup or two every 10-15 seconds while idling and about the same at highway speeds. there is a noticeable power loss when accelerating under load but not awful (probably around 30% loss).

truck has around 107K on her. i have owned it since about 75K miles. i bought the truck from my grandfather. to my knowledge he replaced a couple injectors (not sure which ones), replaced headgaskets (OEM) and deleted EGR. i have about 500 miles on my oil change and about 5,000 miles on my fuel filters. EVERYTHING OEM. i drain the water from fuel pump about every 1500-2000 miles.

so far i have checked battery and alternator and all seemed normal. i put a voltage meter on the FICM last night and it maintained 48+ volts during pre-crank and after cranked while holding 2000 RPMS for about a minute. is this a pretty definitive way of diagnosing a bad FICM?

i do not have any type of scanner other than running it by an auto parts store. what should be my plan of attack from here?

 

Get something to read data live and scan for codes.
You can download Forscan for free to a laptop or a couple bucks to a smartphone, then get something like this to plug into the OBD port.
Torquepro in another one guys use.
Without something to read live data and scan things real time is going to make it difficult and perhaps expensive to diagnose.

https://smile.amazon.com/BAFX-Produc...obd2+bluetooth

 

i will try a buddy that has a scanner for his 6.0. it needs to be a better scanner than what a parts store has right?