97 Chevy s10 miss under load

Ok I haver been reading this one, I do have a question for old_master.
I have a 1997 S10 2.2L with a random cylinder misfire. I have replace all sensors except the air intake and cam position. I have replaced the ICM and all coils. New wires, plugs, injectors,timing chain and the EGR valve. I can start the truck as long as I do not let is sit for too long it will not give a P0300 code. It lacks power and is hard to start after it has been driven for a few miles. I took it to the dealer and they told me the #3 coil had weak spark, so I changed it out with no luck. Compression is good fuel pump and regulator are new. I took it to another shop and they told me that they can not determine what it is. What now the engine wiring harness?

Exactly what DTC's are in memory, and what order are they in?
What brand and part number are the spark plugs that you installed?

AC delco plugs and the only DTC is P0300

AC Delco is good, what part number are the spark plugs?
What is the fuel pressure with the key on and the engine off?
What is the fuel pressure 10 minutes after the pump shuts off?
What is the fuel pressure at idle?

It also lopes at the idle at first but no vacume leaks detected.

According to the dealership the fuel pressure is good the compression is good. I have no way to check it myself.

The spark plugs are the recomended part number.

ac41-928

The dealership told you the 2-3 coil pack was bad and it wasn't, how do they know the fuel pressure is good?

Need to start with the basics:
P0300 is almost always caused by a secondary ignition fault. Occasionally low fuel pressure or excessive leakdown will set it also. Some of the auto parts stores rent fuel pressure testers... very easy to check it. 41-928 are the correct plugs, thank you.

Not sure was not there to see it. I will check it and let you know.

Good night