Your timing belt is bouncing around? Or is the belt frayed and looks like a bouncing effect?
1st off I would inspect that belt, it is not cause unless you jumped a tooth, but you would not want it to break on the road...
If the coils can be moved around, move #1 to another location, clear codes and see if it follows the coil, coils when failing can start to show symptoms under a load, reason why idle may still be good. If that doesn't reveal anything continue...
Take spray bottle of water or oil and aim around #1 intake and injector, note any raise or lowering of RPM, would depend if you used water or spray oil, water it would go down and oil may rise with solvents if there were an intake manifold leak. Any vacuum runners near #1, if they are leaking could cause performance issues...
If that didn't reveal anything, compression test, all plugs out after a warmed up engine, pull connector to coil pack off so you don't get zapped by a plug wire, fuel pump fuse too if you can access it, and wire open the throttle while testing, somewhere in neighborhood of 150-160# would be good reading, taking off top of my head from previous experience...
If still stumped then injector or some other electrical component or connection, but try what I posted and see if those steps take you in right direction... good luck...
Also when looking around an engine compartment if you think you see a ground connection that may be corroded, clean it up, sand down bolt-where it connects-connector and grease them up and re-connect.. remember the negative on a battery is where all the power comes from, that is where the excess of electrons are stored and even some techs will overlook a bad ground when troubleshooting...