fuel injector test ?
 

I am in the process of changing the spark plugs on my 97 E150 and would like to test the fuel injectors as it is apart, the reason that I am changing
the plugs is the motor would start to skip under a load, driving at 35 MPH
no skip any faster it will start to skip. The plugs removed look pretty good
motorcraft except one of them, doesn't look like it was firing, carboned up.
Is there anyway to test the fuel injectors ? or the coils ? Any info is appreciated . Thank you Jim

There were a few engines available that year, can you tell us which engine is in your vehicle?
Each engine had a different ign system.
Some had coil on plug , some had distributors with attached or remote ign modules. Important to get proper info.
How many miles on the clock?

5.4 coil on plug 97 Econoline, close to 175 thousand miles on it

Don't know what kind of equip you have to work with, but If no test equip, after you replace the plugs let us know if the misfire is still taking place and which cyl.had the fouled plug. If the coils have never been replaced with that mileage it is way past that time. Most folks are not aware that a defective coil on that system can wipe out the vehicle computer with a voltage spike. Those computers can get expensive and it is much cheaper to replace all the coils.