Like so many other 3.4 owners I ended up getting these codes intermittently on my 4Runner a couple months ago which was about a month after I decided to retire my old 86 1st gen from daily driving to something more reliable. I have an Ultra Gauge so I am able to look at the CEL codes wheb they happen and I would get a pending P0305 than the P0305 would occur (Flashing CEL) than about a minute later I would get the combined P0300, P0302 & P0305 codes.
By researching this and other forums as well as using the FSM I started to diagnose the problem. Here is what I did which pretty much was in step with the trouble shooting procedure:
1st thing - new NGK Plugs and wires which are Standard Ignition #5605. The old plugs looked in normal condition except the #5 was darker than the rest. -- Result no change
2nd thing - cleaned MAF sensor with CRC MAF cleaner. It was filthy and definitely needed it but there was no change to the error code occurrence.
3rd Thing replaced - PCV Valve with a Standard Ignition part # V388. Result no change to CEL
4th thing - replaced coil pack on the #5 cylinder. I assumed that since both the 2 and 5 spark plugs are fired by this coil pack it must be the problem. Again I used the Standard ignition part # UF-156. There was no change in performance.
5th thing - I decided to replace fuel injector #5. My reasoning on just one was that I assumed that because P0305 started the chain of reactions and P0302 came slightly afterwards the P0302 was caused by changes in the ECMs control of the coil pack to compensate for P0305 and not an issue with that cylinder. I used Standard Ignition Fuel injector #fj585 and ordered 2 seal kits SK53. (Note the seal kits are not correct, they fit a 22RE fuel injector not a 3.4L). I installed the fuel injector today and the CEL is gone with no codes. The old injector had no resistance and was definitely bad. I test drove it up and down some PA mountain passes today and the engine runs better than it has since the day I bought it.
I am not going to say how much I paid for the parts because it is not fair to everyone since I get them at a huge discount as a dealer for them. However I can update everyone if issues do arise with these parts. I know they are not Toyota OEM parts but because I sell standard ignition parts at my store I feel compelled to test how well they work.
By researching this and other forums as well as using the FSM I started to diagnose the problem. Here is what I did which pretty much was in step with the trouble shooting procedure:
1st thing - new NGK Plugs and wires which are Standard Ignition #5605. The old plugs looked in normal condition except the #5 was darker than the rest. -- Result no change
2nd thing - cleaned MAF sensor with CRC MAF cleaner. It was filthy and definitely needed it but there was no change to the error code occurrence.
3rd Thing replaced - PCV Valve with a Standard Ignition part # V388. Result no change to CEL
4th thing - replaced coil pack on the #5 cylinder. I assumed that since both the 2 and 5 spark plugs are fired by this coil pack it must be the problem. Again I used the Standard ignition part # UF-156. There was no change in performance.
5th thing - I decided to replace fuel injector #5. My reasoning on just one was that I assumed that because P0305 started the chain of reactions and P0302 came slightly afterwards the P0302 was caused by changes in the ECMs control of the coil pack to compensate for P0305 and not an issue with that cylinder. I used Standard Ignition Fuel injector #fj585 and ordered 2 seal kits SK53. (Note the seal kits are not correct, they fit a 22RE fuel injector not a 3.4L). I installed the fuel injector today and the CEL is gone with no codes. The old injector had no resistance and was definitely bad. I test drove it up and down some PA mountain passes today and the engine runs better than it has since the day I bought it.
I am not going to say how much I paid for the parts because it is not fair to everyone since I get them at a huge discount as a dealer for them. However I can update everyone if issues do arise with these parts. I know they are not Toyota OEM parts but because I sell standard ignition parts at my store I feel compelled to test how well they work.
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