Intermittent P302 Fault Code

[WrenchTech]

I started my 4runner on a rainy morning a couple days ago and as I pulled away I could just barely feel that the engine was misfiring. The check engine came on. The next time I drove it I didn’t feel the misfire anymore. I drove around for a couple days with the engine light on and then I cleared it. I’ve been driving for about a week since then and the check engine light has stayed off.

Any thoughts on what the problem might have been?

I remember back in the good old days, before electronic ignition, damp weather could cause bad spark plug wires to short out.

This rig is a ‘99 with the 3.4 and it’s got close to 300,000 miles on it.

 

[Heyduke]

Likely a fuel injector, or an ignition coil... welcome to the club /

 

[T.Tech]

Most likely plug wires. If they’re old the insulation cracks and the moisture in the air causes electricity to “leak” out. You can test them by spraying wires with water and see if it starts misfiring, or look for carbon tracking on wires.

 

[brillo_76]

Possiblies of wires, plugs, coils or injectors.

Wires can check out with resistance and still have the insulation failing. Like an other user suggested a mist test and night so find that issue.

Plugs only last so long and can fail. Mostly when they go that's it.

Coils can be tested and we several threads on here on how that can be done.


Lots of folks say they have injector issues and they need tested or replaced. I must be an odd ball as I haven't had any Toyota injectors fail on me in 30 years.

However, I do treat my gas several times a year with fuel injector cleaner so maybe that helps. Or maybe I just lucky. Hard to say.

Sent from my SM-J337V using Tapatalk

 

[davedadude]

2000 T4R 2.7L - Ignition coil issue?

2000 T4R 2.7L Base. 215k Miles

New to the club, just bought my T4R this past weekend and drove great for 2 days, until the original radiator started leaking at the top plastic piece and now I have a P0304 code. Running horrible, shaking etc.

According to the VIN, I should have spark plug wires, but I see 4 direct ignition coils on the plugs. Anyone seen this before on the 3RZ engine?

The tag on the engine says X3RZ-W84 but the tag under the hood says 3RZ-FE RZN.


Sorry to hijack this thread, i'm trying to look for parts on this engine but according to the VIN, this shouldn't use direct coil on plugs. For my own sake, i'm gonna replace all plugs and coils but I cannot find parts cause of this mixup?

Owners swear they never swapped engines in the 12 years they owned it, but after reading a few posts here, seems this might be a Federal Emissions engine? The build date is 12/99. Could this account for the coils vs plug wires? I removed 1 coil, but cannot find this part or cross reference anywhere.

I attached pics, engine is filthy... todo item.

I tried to create a new post, but i'm new so it wont let me.

Thanks everyone!

 

[JMat]

I'd pull the plug and wire and check for any arcing... My bet would be on the plug wire because I had the exact thing happen to me. When it started it was only when it was damp out.

 

[gamefreakgc]

2000 T4R 2.7L Base. 215k Miles

New to the club, just bought my T4R this past weekend and drove great for 2 days, until the original radiator started leaking at the top plastic piece and now I have a P0304 code. Running horrible, shaking etc.

According to the VIN, I should have spark plug wires, but I see 4 direct ignition coils on the plugs. Anyone seen this before on the 3RZ engine?

The tag on the engine says X3RZ-W84 but the tag under the hood says 3RZ-FE RZN.


Sorry to hijack this thread, i'm trying to look for parts on this engine but according to the VIN, this shouldn't use direct coil on plugs. For my own sake, i'm gonna replace all plugs and coils but I cannot find parts cause of this mixup?

Owners swear they never swapped engines in the 12 years they owned it, but after reading a few posts here, seems this might be a Federal Emissions engine? The build date is 12/99. Could this account for the coils vs plug wires? I removed 1 coil, but cannot find this part or cross reference anywhere.

I attached pics, engine is filthy... todo item.

I tried to create a new post, but i'm new so it wont let me.

Thanks everyone!

You have a 2000 model year even though the build date says 99 (takes a while to ship it to a dealer in the US and then sell it). You do have a coil on plug design, the distributor based ignition systems were gone several years before.

To help diagnose your P0304 code, swap the coil pack with the one next to it. if the code moves and become a P0303, it's the coil pack. If it doesn't, replace the spark plugs (cheapest item on the list). If that doesn't solve it, look into cleaning or replacing the offending fuel injector. Those coil packs may not be the OEM part from 2000 but that doesn't mean they don't work. I believe the OEM unit for the 4 cylinders are DENSO coil packs but don't know for sure 100% since I don't own one.

 

[davedadude]

You have a 2000 model year even though the build date says 99 (takes a while to ship it to a dealer in the US and then sell it). You do have a coil on plug design, the distributor based ignition systems were gone several years before.

To help diagnose your P0304 code, swap the coil pack with the one next to it. if the code moves and become a P0303, it's the coil pack. If it doesn't, replace the spark plugs (cheapest item on the list). If that doesn't solve it, look into cleaning or replacing the offending fuel injector. Those coil packs may not be the OEM part from 2000 but that doesn't mean they don't work. I believe the OEM unit for the 4 cylinders are DENSO coil packs but don't know for sure 100% since I don't own one.

Sure enough... Swapped coils from 4 to 1, got P0301. Had to go to dealer to help find my part# since this VIN comes back using plug wires, not coils. After a bit of digging, they helped me conclude that a coil from a 2004 Tacoma 2.7L will work, so looks like that's my engine.

 

[raulb21]

I started my 4runner on a rainy morning a couple days ago and as I pulled away I could just barely feel that the engine was misfiring. The check engine came on. The next time I drove it I didn’t feel the misfire anymore. I drove around for a couple days with the engine light on and then I cleared it. I’ve been driving for about a week since then and the check engine light has stayed off.

Any thoughts on what the problem might have been?

I remember back in the good old days, before electronic ignition, damp weather could cause bad spark plug wires to short out.

This rig is a ‘99 with the 3.4 and it’s got close to 300,000 miles on it.

I had an intermittent misfire, mine ended up being a single fuel injector. I lean toward this because when I did the good 'ole fuel injector test with some carb cleaner and a battery, it would work sometimes and other times wouldn't get anything. (explains the lapse in the misfire occurrences) That solved mine, hopefully that helps a little.