my early o4 is not running right i pulled code p0275 so i hooked up my snapon scanner and done the cylinders contribution test cylinders values are showing. at 636 rpm
cyl 1, -1 to 0
cyl 2, 1 to 2
cyl 3, 1 to 2
cyl 4, 1 to 2
cyl 5, 0 to 1
cyl 6, 0 to 1
cyl 7, -3 to -2
cyl 8, -5 to 0
and at 1200 rpm
cyl 1, 0 to 2
cyl 2, 0 to 1
cyl 3, -3 to 0
cyl 4, 0
cyl 5, -1 to 0
cyl 6, 0 to 1
cyl 7, -4 to -2
cyl 8, 1 to 3
FICM
FMP 48.5
FVP 13.5
FLP 13.5
what sould i do next

 

7and 8 and toast. Although a P0275 is number 5 cylinder contrbution,check your harness.Looks like it had low fuel pressure. Depending on your money I'd look into changing g them all with Ford injector or just those 2 and reseal the rest and add Archoil to it. You can also try that first,but it's a short term fix

 

Okay I'll see how much they are to see if I can change them thanks

 

How many miles and hours on the engine? If indeed, both 7&8 are the problem, both are on the driver's side under the ficm and relatively easy to replace.
How long have you had the Blue Spring installed?
You might want to replace all of the injectors if you've got a spare 2k.
I'd confirm the injectors and replace just those myself if miles are under 200k.
Just my opinion.

 

7 is on the passenger side and 8 is on the drivers side.

 

Yep, thinking about my Expy cylinder sequence. Thx for correcting.

 

151k on motor not sure about the hrs. Blue spring update 3 weeks ago I did do the buzz text and that was good. What's the best way to tell if it is the injectors going out if they are can I rebuild them. I don't have a lot of money right now. I did just order rev x oil and fuel kit I hear it's the best stuff to use

 

Being a GM guy I did the same thing. I'd try the cheap route first. Schaffers oil and Motorcraft filters. Amazon has it on their site for 25.00 a gal. Archoil is there too. You can change the injectors after the oil change down the road.

 

I'm a gm guy to this was my first ford and first diesel I drove gm for 46 years this was a big change for me but I really like this truck an I'm the 2nd owner

 

Ya,I know the feeling. Once you go to the dark side you can't go back..............