Missing under load
I had a chevy blazer in the shop here recently that had a nice idle , on the test drive it had a misfire when you would try to accelerate quickly , as long as you accelerated normal it was fine.
I would have bet that it was a fuel issue, just felt like it was starving for gas.
Monitored fuel pressure gauge and was steady during symptoms, had my labscope hooked up to the cam and crank sensor and caught the crank sensor cutting out when it acted up.
I always try to make sure I am replacing a known bad part, it can get expensive guessing on these efi vehicles.
Here is a shot from the lab scope , bottom screen shows crank sensor in yellow when acting up. Green trace was the cam sensor :