I get what you are saying Cedric and I must have maybe elaborated a bit so here goes
If your Patrol starts up fine in the morning and doesn't misfire or smoke for the first 30 seconds or so they probably are ok
Bad injectors tend to drip and loose pressure over night, so on startup they need a little time to get the right pressure from the pump.
Also they tend to send out puffs of smoke out the exhaust and not an even amount if that makes sense in any way.
The reason I am saying this is because I sent a set of injectors to Bosch last week just to test, clean and set the pressures correctly. The injectors was 10 times worse after that and I had to remove them again and sent them in to do it over and set the pressures to what I gave them.
So in the end, something that was fine and had no problem cost me about 5 hours of labor to get it back to its original state.