1998 Taco, persistent p0306, ECU?

Hi,
V6 1998 TRD, lightly abused for 135k miles. Throwing 0306, had plugs, wires and bunch of other stuff replaced. Ran OK for 300 miles then back to rough running with CEL.

After a while, it goes open loop and runs OK for 10 minutes or so.

Since plugs and wires are new, what's next? ECU? Don't trust the shop that took $1650 to not fix the issue to take another go at it (they took care of other issues, so it wasn't a waste of time)

 

Bad/dirty injector? Low compression? Those will also cause a misfire code.

 

Good call on the injectors; I forgot to mention they blew a can of injector cleaner through 6. That doesn't mean that injector is gtg, though.

I don't know that they checked compression. Would bad compression come and go like that?

 

Depends on the cause of the low compression. Sticking valves can cause periodic low compression.

 

Thanks. Hopefully I can find a mechanic to look at it - the one I used for years retired, and the new guys aren't cutting it.