#7 Injector fault and other questions

[J-ROCK]

I just did a buzz test and had a #7 injector open circuit high side open fault.
Truck does have a miss that seems to get slightly better when warm.
Obviously I'll test the OVH tomorrow while it's in the shop but wondering if I do need to replace an injector whats the cheapest most reliable solution to go with?

Truck is pretty much stock other then DIY intake, muffler delete and Superchip programmer.

This truck will not run properly if it's not plugged in, it's will start and run poorly until warm even on the hottest of days and this time of year it won't even run without being plugged in. I'm going to test the GP system as well tomorrow and I've read every thread there is to read about cold start issues here but know one ever seems to find an answer, the closest thread I've found to my issue is this one...
another hard start, NOT THE GPS!

I suppose it could be compression but wouldn't it smoke and burn oil if that was the case.