misfire...P0302.

[Puerco]

have a P0302 code on a 1999 4runner limited.
changed plugs and wires,truck started great. Pulled the EFI fuse out to clear the codes, after I started it and shut it off. While on a test drive it began to misfire AGAIN.
I am thinking injector or coil....if the coil is going bad will it send MULTIPLE misfire codes since the coils are shared?
it has not had a check engine light come back on ,yet.
and yes I changed the coil boots as well.
thanks for your cooperation and patience.

 

[Bad Luck]

have a P0302 code on a 1999 4runner limited.
changed plugs and wires,truck started great. Pulled the EFI fuse out to clear the codes, after I started it and shut it off. While on a test drive it began to misfire AGAIN.
I am thinking injector or coil....if the coil is going bad will it send MULTIPLE misfire codes since the coils are shared?
it has not had a check engine light come back on ,yet.
and yes I changed the coil boots as well.
thanks for your cooperation and patience.

I had a bad ignition coil and it never set a check engine light or a pending dtc. The coil was within resistance values that Toyota stated, but was higher than the other two. Check the resistance of each coil pack between the two terminals of the coil connector, and then check the resistance between where the spark plug wire and the spark plug boot (at the bottom of the ignition coil).

 

[Jazbo]

I know this is an older post, but apparently I'm to new to start a new thread.

I am having a P0302 code on my new to me 97 4runner. I had just finished a tune up, (air filter, fuel filter, seafoam, spark plugs, oil change, MAF, TB and IAC clean up, new TPS) and everything was running excellent, other than a high idle that I thought would go away after the computer relearned the cleaned IAC. Anyway, my wife brought it back from being aligned on it's second run after the tune up and it still had a high idle and had just gotten a P0302 code.

I have done everything I can think of, including swapping coil and spark plug positions, looking for any obvious vacuum leaks, and even buying and installing a new fuel injector. Still the code remains and I'm about out of ideas. I also pulled the plug wire and got spark to a ground, so I assume the wires are good. Any suggestions? Thanks in advance

 

[Tucson4runner]

I know this is an older post, but apparently I'm to new to start a new thread.



I am having a P0302 code on my new to me 97 4runner. I had just finished a tune up, (air filter, fuel filter, seafoam, spark plugs, oil change, MAF, TB and IAC clean up, new TPS) and everything was running excellent, other than a high idle that I thought would go away after the computer relearned the cleaned IAC. Anyway, my wife brought it back from being aligned on it's second run after the tune up and it still had a high idle and had just gotten a P0302 code.



I have done everything I can think of, including swapping coil and spark plug positions, looking for any obvious vacuum leaks, and even buying and installing a new fuel injector. Still the code remains and I'm about out of ideas. I also pulled the plug wire and got spark to a ground, so I assume the wires are good. Any suggestions? Thanks in advance

Did you replace all injectors or just the one?

Sent from my SM-N975U using Tapatalk

 

[gamefreakgc]

I know this is an older post, but apparently I'm to new to start a new thread.

I am having a P0302 code on my new to me 97 4runner. I had just finished a tune up, (air filter, fuel filter, seafoam, spark plugs, oil change, MAF, TB and IAC clean up, new TPS) and everything was running excellent, other than a high idle that I thought would go away after the computer relearned the cleaned IAC. Anyway, my wife brought it back from being aligned on it's second run after the tune up and it still had a high idle and had just gotten a P0302 code.

I have done everything I can think of, including swapping coil and spark plug positions, looking for any obvious vacuum leaks, and even buying and installing a new fuel injector. Still the code remains and I'm about out of ideas. I also pulled the plug wire and got spark to a ground, so I assume the wires are good. Any suggestions? Thanks in advance

The only thing you haven't changed is the spark plug wires. They are not too expensive, look for NGK wires online on Rockauto.com or another online seller.

Not to be rude or anything, but you are checking cylinder 2 correct? Driver's side front cylinder?

The high idle is probably your new TPS. Normally these are not messed with due to issues that arise.

 

[Jazbo]

Did you replace all injectors or just the one?

Sent from my SM-N975U using Tapatalk

I only replaced the cylinder 2 injector.

 

[Jazbo]

The only thing you haven't changed is the spark plug wires. They are not too expensive, look for NGK wires online on Rockauto.com or another online seller.

Not to be rude or anything, but you are checking cylinder 2 correct? Driver's side front cylinder?

The high idle is probably your new TPS. Normally these are not messed with due to issues that arise.

That's true, I just assumed the wires had to be good since I was getting spark to ground from them.

Yes, driver side front.

I was actually getting the high idle prior to replacing the TPS, it started when I cleaned the throttle body and IAC. I replaced the TPS due to the rpms dipping before they would go up when I applied the throttle. It also showed a dip on throttle position on my scanner.

Is there any way that a malfunctioning IAC could cause a cylinder 2 misfire? I figure it could be like a vacuum leak, but I don't understand how it would stay with one cylinder.

 

[Jazbo]

The only other thing that I can think of that might be relevant is that when I was testing it after replacing the injector, it would run fine and then miss a little, back and forth as I was waiting in my drive to pull out. Then I accelerated and got the flashing CEL, when I let off the gas it went solid but I could tell it was missing some as I came back home.

 

[TheDurk]

The only other thing that I can think of that might be relevant is that when I was testing it after replacing the injector, it would run fine and then miss a little, back and forth as I was waiting in my drive to pull out. Then I accelerated and got the flashing CEL, when I let off the gas it went solid but I could tell it was missing some as I came back home.

I would do the wires, and if that doesn't do it, time for a compression test.

 

[Jazbo]

I'll definitely do the wires. I have one more question while I'm waiting on a compression tester to come in. If my head gasket was out wouldn't my spark plugs look off or a misfire on adjoining cylinder? Also had my valve cover off to replace the gasket while I had my intake off for the injector, everything looked good in there and the valves seemed like they looked good from what I could see in the intake. Don't know a whole lot about all this but trying to learn.

 

[Bad Luck]

If my head gasket was out wouldn't my spark plugs look off or a misfire on adjoining cylinder?

A failed head gasket doesn't always happen between cylinders. Sometimes it can happen between the cylinder and a coolant or oil passage. Only a head gasket failure from one cylinder to another would cause the two cylinders to exchange pressure.

Where did you get the new injector?

 

[Jazbo]

A failed head gasket doesn't always happen between cylinders. Sometimes it can happen between the cylinder and a coolant or oil passage. Only a head gasket failure from one cylinder to another would cause the two cylinders to exchange pressure.

Where did you get the new injector?

Yes but my oil and coolant look great.

O'Reilly's. It was the only place here that had one in stock and I'm needing to get this back running asap.

 

[Bad Luck]

Yes but my oil and coolant look great.

O'Reilly's. It was the only place here that had one in stock and I'm needing to get this back running asap.

I would have tried swapping the injectors before buying a new injector. How did your fuel injector wiring look?

 

[Jazbo]

Probably would have been a good idea in hind sight. I just didn't want to have to year into the intake twice if it was a bad injector. The wiring looks good as far as I can tell visually.

 

[Bad Luck]

I would recommend using a noid light and checking all the injectors you can get to with that. Youtube can do a better job on explaining how to use a noid light than I can

 

[Jazbo]

I changed the spark plug wires and the miss has gone away as well as my high idle. It's a huge relief but makes no sense to me. How could bad wires cause all that and yet still have a strong spark to ground?

 

[TheDurk]

I changed the spark plug wires and the miss has gone away as well as my high idle. It's a huge relief but makes no sense to me. How could bad wires cause all that and yet still have a strong spark to ground?

Off the top of my head....corrosion in the plug connector, or insulation fail sucking energy when in operating, but not test position. Try the old farmer test of running the engine in a totally dark garage. (Vent the exhaust!!!!!) You might SEE the leakage.

When wrenching, don't fall into the trap of overthinking why it might NOT be the logical cause.

 

[Bad Luck]

I changed the spark plug wires and the miss has gone away as well as my high idle. It's a huge relief but makes no sense to me. How could bad wires cause all that and yet still have a strong spark to ground?

Bad spark plug wires can still allow a weak spark. GM has a specific spark tester that no one uses that requires a specific amount of current to make a spark. Fancy.

 

[Jazbo]

Thanks a lot guys! I'm the worst at overthinking things, especially since I felt I had eliminated ignition. Thanks again

 

[gamefreakgc]

I'll definitely do the wires. I have one more question while I'm waiting on a compression tester to come in. If my head gasket was out wouldn't my spark plugs look off or a misfire on adjoining cylinder? Also had my valve cover off to replace the gasket while I had my intake off for the injector, everything looked good in there and the valves seemed like they looked good from what I could see in the intake. Don't know a whole lot about all this but trying to learn.

Your coolant levels would drop, that's the most obvious sign. That or coolant in your oil. If both fluids are good you can rule out a head gasket. Currently doing that job on my dad's Sonoma. Not really sure that truck is worth saving but it's his truck...

You are on the right track though. New wires & compression test will bring clarity to this issue.