I have 2004 RX330. I noticed a slight hiccup in RPMs that only lasted 2-3 seconds while idling. Two days later engine light came on. Throwing codes PO301 Cyl 1 misfire, PO302 Cyl 2 misfire.
So I need spark plugs replaced. Before I could schedule the work, engine light goes out and there hasn't been any sign of misfire in RPMs.
Should I get the plugs replaced anyway?
Fuel economy and performance don't seem to be affected.
Thank you

 

One rpm hiccup probably not a worry. Will the codes clear? Maybe run a cleaner or up your gasoline grade.

If the 330 is like the 400 and the engine is the same then the rear bank cylinders are tricky to access.

are the plugs original? They are on mine a 15 year old 400. For me it will be a mechanic job

 

I'd swap them out & have the coils checked as well. I'd replace the bank 1 coils as well. If a shops doing it, have them also do a injector cleaner service as well... Basically a portably machine, thats self contained. The tech will undue the inertia switch connector & then undue the fuel pressure line going to the injector rail & hook up a separate line from the machine to the injector rail which also contains about a 1/2 gallon of the cleaner & then the pump that runs it is hooked up to your battery to power the pump. The vehicle then is started & sits there idling till it runs out of the cleaner solution. When I worked in shops & the body shop next door to the service dept, I always did mine & my wife's gas vehicles & it does a great job.....

 

how many miles on the rx? lexus says the spark plugs should be changed every 120,000 miles so it might be time to change them out. As far as type of gas; well if you have a 330 that can run regular 87, but if its a 350 like mine; those are supposed to run premium only. If you go to change out spark plugs; look for guides on here as there are a number of excellent guides. The front ones are super easy takes maybe 20 minutes if that to do; but!; the rear ones are a royal PITA!!!!! those can take 3-4 hours to get done because of all thats involved.