Here is a comment from the TWM site that Rusty suggested:
Most peak and hold drivers will drive both high and low resistance injectors but, under no circumstances, should peak and hold injectors be driven with saturated drivers. I mistakenly ran short time without 5 ohm ballaster resistor in line with P&H injectors. Wonder if I killed their life? My used injectors that came with Bruce's package were cleaned and flowed before mistaken running. One died shortly and I replaced with a rebuilt auto store one. Now I believe another was has an anomally. Yuk!

Should I trade them all out before I fly?

Makes me glad that I put the injector disable switches in and have 2 per rotor.

Bernie