I replaced the spark plug in that cylinder, but to be on the safe side, I actually brought some OEM parts from Lexus and replaced all my spark plugs.

 

awsome, thanks for this. I so hope it’s not the same issue as the Tacoma folks. Burnt valve that require cyclinder and head replacement.

 

Cylinder mis-fire can also be igniter issue.
You can swap locatoin of the igniter to locate which one is defective, if that is not it, there is a possibility of a head gasket issue....but hopefully that is not the case here.
Note that the original poster did use fuel injection cleaner as a possibillty of an injector issue.....
Keep us posted

 

thanks Lexicon. I cleared the code and put in half a bottle of redline fuel injector cleaner in 3/4 of a tank. Going to run the tank, fill with premium gas and use the other half.

So far, first few trips, still a slight stutter sometimes, no cel yet.

 

P0303 was ignition coil for me. First part to go after 86k

 

Narci,
If it comes to fuel injection cleaner, my go to is Royal Purple Max cleaner... works for me.
Important to follow the correct dilution per instructions or even make it more concentrated to get the job done.
Good luck w Troubleshooting...

 

thanks. Tried Redline and Toyotas own injection cleaner. No go. Car still rough, stutters and misfires at times. P11EE still shows up after a day or so after every time I clear it.

Techstream stated code is an air fuel imbalance (port). Had all 4 port injectors replaced. I could have done 1 but might as well do all 4 since the labor is about the same. Car runs like new now.