2002 Toyota Highlander Q&A
2002 Toyota Highlander Question: I have logged fault codes P0300, P0301, and P0303. What is the problem?
Misfires are noticeable. I don't feel like I can go over 50mph. These displayed about 20 miles after filling up a nearly empty tank. I can't siphon a gas sample to check for water because a rollover spillage blocking device is in the tank. I replaced plugs and swapped the coils to no effect. I cleaned the MAF to no effect. I can't hear or see an intake problem. I have the Torque Pro app but don't really know what to look for to diagnose this problem. I did notice my STFT2 was over 20% while STFT1 was -5%, but MAF at warm idle is 2.4g/s, load at WTO is 85%. If you could give me pointers on how to check 02 sensors or other possible culprits with the Torque Scanner app, I'd be very grateful! - sparejayden
COULD BE ELECTRICAL ISSUE OR INJECTOR - globalhelper
You have the information that we need to start testing for the misfire, and the bank to bank fuel trim suggests at the least a potential downstream O2 sensor fuel trim issue, or it could be an airflow problem such as a cam out of time or a restricted exhaust on just one side. The bank taking away fuel would potentially be the side that isn't breathing as good as the other bank. Miss-fires kill catalysts, this needs addressed before it gets worse. - cardocIII
You did swap the known good coils, 2 & 4 with the 1 & 3 coils i assume? Back to the basic tests, compression, vacuum, ignition and fuel. You should find the problem with those tests! If not equipped to complete, get some hands-on help. - pushrod