96 F250 197,000 miles. Truck went into the shop to have a oil cooler replace, valve cover gaskets and I believe 2 glow plugs replaced. having a problem with injector on #2 and 4 being stuck open I have tried different injectors. I've tried moving those injectors around and every time 2 and 4 are stuck. Buzz test blinks 2 and 4 but immediately after clears and says it's good. Anyone have any ideas it's driving me crazy.

 

It's got to be something in the wiring to those two holes. Did the shop put new pigtails on? They may have gotten a couple wires crossed.

 

Like ReBilld said it is most likely a wiring issue if the problem does not follow the injector as in your case.

Below is handy wiring diagram for the OBS system. Check the front driver's side UVCH connector for any obvious signs of failure. Could also be inside the valve cover, and may not have been hooked up or not seated all the way into the injector by the shop.

 

also check what glow plugs the shop put in. most likely autolites. if so, pull them out and replace with motocraft ZD-11's before they burn out and swell the tips in the head.

 

Now if the shop did not replace the pig tail on the driver side would this have anything to do with it. Not sure if they didn't just courious.

 

it could if there are burned pins in it.

 

Simple cheap thing to try: Swap the undercover harness for 2 & 4 with the one from 6 & 8, and see if the issue moves to 6 & 8. if so, just get a new UCVH.
One thing to eliminate anyway.

 

So so here's what I got. Went and messed a bit today. All valve cover plugs appear to be fine. He said 2 and 4 but everyone calls it different. Figured out it's the 1st and 2nd cylinder on the driver side. Does anything stick out about the wires? I did not buy oem valve covers so colors don't match. This is what I have so far. Would appear orange is connected to a orange and white stipe and yellow is connected to a white or grayish wire

 

I'll take a look at mine here in a few. I'm running Dorman valve cover gaskets on mine, so I'll see if the colors match. It's hit or miss with those Dormans, so the issue could be under your valve covers.

Yes, 2 & 4 cylinders are the front two on the driver's side. Looks to be a couple of nicks on the insulation of the wires prior to the wire splices, so check those over carefully. The shielding covers the 3 center wires as those power the injectors with the center wire being the high voltage feed for both 2 and 4 injectors. That could be the common problem if neither injector is firing. The odds are that the problem is with one of those splices or under the valve cover.

 

It looks to me that butt connectors were used to splice the wires. If so that is no good. The wires need to be soldered together. I learned the hard way on my 97. They worked for a while, then the truck developed a miss that would "fix" itself, then progressed to a miss all the time. After cutting the connectors out, and soldering the wires, all was good.

 

^^^this butt connectors ain't worth a chit, solder and heat shrink for best results.

 

And one wire at a time so you don't have to think about what goes where.