At this point my head is saying fuel injector. :smile:

I "think" the 355 is just a reported misfire on cylinder 5 actually, described as secondary spark fault. I could be mistaken though.

 

Check the connector for the ignition coil for #5 cylinder. This is on the rear bank, closest to the left side of the engine compartment.

ECM/PCM/ECU all mean the computer.

 

You have a failing coil #5

I have '05 Avalon and have had several coil failures. Here's how to read the info.

The OBDII reader kicks out a P0300 code (general ignition failure) and a P035x code. It also kicks out p0301-P0306 basically saying all coils have registered a misfire problem. Clearly, all coils can't be bad or the engine wouldn't run.

The key is the P035x code. The last digit specifies which coil is bad. I previously had a P0352 code and the dealer replaced coil 2. I later had a P0354 code and I replaced coil 4. Problem solved.

I eventually had a rear bank coil failure. I replaced all three coils and the plugs while I had it apart. I'm guessing the failure is a grounding issue so I used "Wells" brand coils, which are said to have the grounding issue engineered out.

http://www.wellsve.com/video_ignitioncoiltesting.html

Clearly the Toyota OEM coils were failing so I didn't want those. I put three Wells coils in the rear bank and have had no issues since. I kept the two good OEM coils as spares should a front coil fail again. The fronts replace in ten minutes.

Hope it helps.

 

Basic engine OK?

Has anyone checked compression? How about using a noid light on the fuel injector connector? Just because our engines are good for eating coils does not mean EVERY misfire on this engine is caused by an ignition failure.

If compression checks out and there is a flashing noid light then there could be a fault with the ignition system. ECM and PCM and ECU are all interchangeable terms for the computer that controls the fuel, ignition and emission systems. DENSO electronics are among the best in the world and their PCMs rarely fail (unless it is a 2002 vintage RAV4)

If the fault comes down to being in the ignition system, check the coil connector closely. The latches break when you breathe on them and don't allow the connector to fully seat and make a good connection. Connector shells are available at the dealer so the wiring would not need to be soldered, just the wires swapped from the broken shell to the new shell.

I would replace all the coils and spark plugs in the rear with only DENSO. The cylinder you are most concerned with is the one closest to the driver's side of the vehicle on the rear bank.

 

"DENSO electronics are among the best in the world...." "I would replace all the coils and spark plugs in the rear with only DENSO."

I'd agree, in general. However, the coils that fail over and over and over and over....are Denso. I opted to try something else, given Denso's track record on this part, and have had no failures. Only the Denso coils have failed and I have four non-Denso coils on the engine.

If the fault comes down to being in the ignition system, check the coil connector closely. The latches break when you breathe on them and don't allow the connector to fully seat and make a good connection. Connector shells are available at the dealer so the wiring would not need to be soldered, just the wires swapped from the broken shell to the new shell.

You can put a zip tie around them, broken or not, and they stay together as well as they do with the brittle, factory, plastic clip. Cleaning the connectors with electronic cleaner to ensure the connectors are clean works well too.

People often get caught in "the manufacturer makes the best parts" trap, which isn't always true. Remember, Toyota has many parts made by other OEMs so what you buy from Toyota isn't always made by Toyota.

 

I can appreciate and respect the voice of experience and I'm not looking to get in a spitting contest. However, with respect, some very smart and experienced people use to teach us that the world was flat. That didn't make them right.

Based on the info you provided, my OEM coils were likely Diamond and not Denso. I recall they had "Toyota" stamped on them but I don't recall other markings. There may or may not have been some. Your info kind of illustrates the risk of going to the dealer. Toyota changes OEMs so you don't know what you're actually buying regardless of the inflated price you're forced to pay.

Wells says the are using marine grade grease in their assembly process to help reduce grounding failure due to moisture. You can believe it works or doesn't. Again, more information to help the DIY make an informed decision.

http://www.wellsve.com/advantage_coilonplug.html