Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Lots of work so far. Steady miss, multiple cylinders. Swapped plug wires due to a failed primary wire (found this in 2 pieces when I got to where I could shut it down), and an arc trace on a boot, about number 2. Current wire set is motorcraft, nice condition, no corrosion. Swapped cap and rotor from donor Ford, no change. Plugs are old, but steady spark on gap tests, normal lean color on condition. PIP scope trace is consistent and good on Voltage, 9.5 low to 13.5 high. I watch SPOUT trace against it and there is a symptom I cannot interpret. I expect the PIP to drop voltage exact time SPOUT voltage shoots up. However a couple cylinders after reference 1 on the scope, there is a wide variation on the two traces, almost evenly split.
Using a Verus, lacking a few accessories, so further tests waiting on some more test gear to analyze the coil fire against the above data. Have not started on fuel diagnostic yet.
Vehicle runs all the time, has never died, has never set a code. Have Ford OEM OBD1 and it just produces the 111 normal result. Severe miss began and I found the split in 2 primary wire. Nothing has resolved issues in a few weeks of effort (winter slow work). Swapping TFI next from a good used one.
