2002 with codes random misfire clynder 1 and 2 misfire

what code reader are you using?

 

1. Since the misfire was only on cylinders 1&2, have you done a compression tests on the cylinders to compare compression pressures? If cylinders 1&2 varies widely with the other cylinders, you either ha e a worn piston rings, or the top gasket has a failure on those particular spots.

2. Have the fuel injectors on those cylinders checked.
A clogged Injector system, would have a misfiring codes, as you do. Notice, sometimes, it could be intermittent.

3. Intermittent electrical harness injector problems.
A failed singanl voltage wire harness from the fuel injector connector to the ECU may have shorted partially. So, even if the spark plugs, ignition coils have being replaced, the issue would still persist.

4. Weak valve cover gasket. If you have a brittled valve cover gasket, engine oil would sip straight into the spark plugs port, and foul the plugs with engine oil.


PS: Try swapping the 1&2 spark plugs to numbers 3&4, and see what happens. If you still ha e same issues on em, the concerned spark plugs might have some hairline cracks on their ceramic insulator.

Also check to ensure the ignition coil connectors are properly connected.
Legends:

1st picture: Fuel injectors from gen2
2nd picture: Sample ignition coil on RX 400h
3rd picture: Valve cover gasket on a rav4



Dxta