Last reported case: 1 years ago
Based on 8 owner reports, 8 from forums)
What is P0303?
P0303 indicates the engine's computer has detected a misfire specifically in cylinder 3, which is a critical powertrain issue that can damage the catalytic converter if ignored. Based on real owner data, this code is most frequently triggered by ignition system failures, particularly in vehicles like the Ford F-150, Honda Accord, and Chevrolet Spark. Owners report it often occurs around 80,000-130,000 miles and can cause noticeable drivability problems.
Common Causes:
- Faulty ignition coil on cylinder 3 (most frequently cited fix in owner reports)
- Worn or fouled spark plugs (commonly replaced alongside coils in maintenance)
- Potential head gasket issues mentioned specifically for Honda Accords by a service manager
Symptoms:
- Engine shudder or vibration, especially noted in Ford F-150 transmissions
- Check Engine Light is illuminated
- Reduced engine power and rough idling
- Occasional traction loss or fishtailing in performance vehicles like the Ford Mustang
🚗P0303 on 2010 LEXUS RX
This page focuses specifically on P0303 issues reported by 2010 LEXUS RX owners. The experiences and fixes below are from real owners of this exact vehicle.
Symptoms Reported by 2010 LEXUS RX Owners:
Parts Often Involved:
What Owners Say
Real experiences from 2010 LEXUS RX owners
“Its currently about 42 degree where I'm at. I recorded the video at the exhaust tip with coil connected for about 3-4 mins to let car warm up at idle. (I was monitoring the codes while it was running and it changed quite a bit, at first just had a P0300, then just a P0303, then a P0300,P0302,P0303, then a P0300,P0301,P0302,P0303) Also it went from a flashing check engine light to nothing, then back, then disappear.”View original
“I re-assembled everything, started it, waited for about 10 seconds for flashing light to come back on but never did. I let it warm up to full operating temp about 5-6 mins and still looked and sounded fine (imo).”View original
“I took some new videos/pictures today which are hopefully better and helpful. I combined them all into one video, all the pictures will be at the end.”View original
“05 RX330 - P0303 (Cylinder 3 Misfire Not Coil or Plug) I re-assembled everything, started it, waited for about 10 seconds for flashing light to come back on but never did.”View original
“05 RX330 - P0303 (Cylinder 3 Misfire Not Coil or Plug) I rented a compression tester from O'Reilly's and checked the rear cylinders compression following @Margate330 DIY write up.”View original
“05 RX330 - P0303 (Cylinder 3 Misfire Not Coil or Plug) 2005 Lexus RX330 , out and about running a few errands and I was about a mile from my house when I get a flashing CEL, VSC and TRAC OFF lights on dash.”View original
“I'm by no means a mechanic but I'm trying to do my best to get the car back on the road. I did confirm based on VIN that my car was made in Canada so I would need the (L) part #s.”View original
“Also should both be replaced or could I do just the one that correlates to rear cylinder? The few videos I saw about this were for Toyota/Lexus but not my exact engine and they both mentioned having a different trouble code that I did (Code 1349) You Tube You Tube”View original
“I recorded the video at the exhaust tip with coil connected for about 3-4 mins to let car warm up at idle. (I was monitoring the codes while it was running and it changed quite a bit, at first just had a P0300, then just a P0303, then a P0300,P0302,P0303, then a P0300,P0301,P0302,P0303) Also it went from a flashing check engine light to nothing, then back, then disappear.”View original
“I combined them all into one video, all the pictures will be at the end. My plan was to run a full compression test on all cylinders today (I've got my EFI fuse pulled according to @Margate330 DIY write up). but don't think my battery was up for it so currently charging my GOOLOO GP4000 Battery Jump Starter to assist.”View original
These are real experiences shared by 2010 LEXUS RX owners on automotive forums and communities. Results may vary based on vehicle condition and repair quality.
About This Data
This page aggregates 8 discussions about P0303 from 2010 LEXUS RX owners across automotive communities.
Success rate (0%) is calculated from posts where owners confirmed whether their fix resolved the issue.
Last updated: 2/11/2025