[Putershark]

If not careful, you could wind up spending a lot more time and effort replacing parts then just taking it to the dealer and pay 1 hour of labor to the have a ECU data dump and code check done...

But in the mean time, one could check some of the more simpler things such as,

1. Battery condition (including water level) to make sure the ECU has enough voltage to operate the engine management system correctly (one of the most simple and forgotten items to inspect) for once voltage drops below 11 to 10.5 volts they get "confused" for a better lack of terms, and cannot make adjustments fast enough to the air / fuel mixture.
2. Check the engine grounds to make sure they are clean and tight (has the same effect as #1) Also check the connections at the Alternator.
3. Pull the plug wires one at at time and with a meter, make sure that any one does not have a lot more resistance than all the others (aboce 10 ohms) thus, breaking down under load. Also look closely at the plug wire boots to make sure your are not grounding out one cylinder to the block as the engine and voltage spins up.
4. Pull the spark plugs and make sure they are not all gummed up with deposits and even not, that does not mean one is not breaking down under load. Pending the number of hours on the engine, it may be wise to just go ahead and install a fresh set of firing pins
5. Check for clean wiring connections to the fuel injectors (pending type of course)
6. Make sure that the engine oil tank is full and the ECU is not shutting down the engine to a limp home mode thinking it is running low on oil
7. Check the fuel lines and filters for blockage or the bulb or fuel line that is cracked and sucking in air.

That is about all I can think of for now, the rest really needs a computer hooked up and talking to the engine ECU to see what is happening in real time.

Let us know how you make out