P0304 code - misfire in cylinder #4
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P0304 code - misfire in cylinder #4
On the wife's '99 4Runner (3.4, 5 spd, 122K miles) I am getting a P0304 code. Ran fine yesterday, drove all over town with no problems. She drove to work this morning and said it was hesitating and vibrating, yet no CE light. On the drive home tonight, same symptoms, then the CE light came on.
When she got home I went to check it out. It definitely sounds like it is missing. Making a ffft, ffft, ffft sound from the exhaust. Pinging under load too. Went to AutoZone to pull the code. Came up with the P0304 and a message saying "The PCM has determined that a misfire has occured in cylinder #4."
First of all, #4 should be on middle driver side correct? What would you guys check first? The plugs and wires are about 2 year old Densos. The coils are probably original. I did the timing belt replacement at 118K, and cleaned the MAF recently too.
Thanks for any help.
Hodag
When she got home I went to check it out. It definitely sounds like it is missing. Making a ffft, ffft, ffft sound from the exhaust. Pinging under load too. Went to AutoZone to pull the code. Came up with the P0304 and a message saying "The PCM has determined that a misfire has occured in cylinder #4."
First of all, #4 should be on middle driver side correct? What would you guys check first? The plugs and wires are about 2 year old Densos. The coils are probably original. I did the timing belt replacement at 118K, and cleaned the MAF recently too.
Thanks for any help.
Hodag
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After that do a compression test if the problem cylinder doesn't "move". Any smoke from the tailpipe? What does the oil look like?
My wifes 4Runner was doing the same thing yers is and I got a busted head gasket. What a joy to behold this holiday season!
Ryan
My wifes 4Runner was doing the same thing yers is and I got a busted head gasket. What a joy to behold this holiday season!
Ryan
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Oil looks good, no smoke from the tailpipe. Those are one of the first things I checked, being that I am a glass half empty kinda guy.
I guess I start with plugs, wires, and coilpack. Ill swap them around to see what happens.
Thanks, Hodag
I guess I start with plugs, wires, and coilpack. Ill swap them around to see what happens.
Thanks, Hodag
#5
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You might want to read over here a well:
https://www.yotatech.com/forums/f2/p303-misfire-detected-100681/
And, starting at post 5, this thread hijack walked through a similar problem:
https://www.yotatech.com/forums/f2/smt6-open-closed-loop-fix-idea-100230/
https://www.yotatech.com/forums/f2/p303-misfire-detected-100681/
And, starting at post 5, this thread hijack walked through a similar problem:
https://www.yotatech.com/forums/f2/smt6-open-closed-loop-fix-idea-100230/
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I would recommend contacting a dealer.
BTW how many miles in your wife’s 4Runner?
Last edited by progress4m; 12-20-2006 at 09:53 AM.
#7
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Unfortunately the dealer will just tell you that the service campaign for that is over. I believe it ended in October of 2004, but they might have put through a few at the end just past that date. I doubt you'll get Toyota to budge on that over 2 years later though.
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Well, heres the story now. Just got in from changing plugs and wires. Number 4 plug was obviously the culprit. Very black and worn compared to the other 5 plugs. Went ahead and changed the wires too (I think they were original).
The truck runs fine now, no ffft, ffft, ffft, no shudder and hesitation. Autozone was closed so I havent cleared the code yet.
What would cause #4 plug to go bad? Faulty plug? Injector going bad? I guess at this point, Im just gonna drive it and wait to see if the problem arises again.
Thanks for the help.
Hodag
The truck runs fine now, no ffft, ffft, ffft, no shudder and hesitation. Autozone was closed so I havent cleared the code yet.
What would cause #4 plug to go bad? Faulty plug? Injector going bad? I guess at this point, Im just gonna drive it and wait to see if the problem arises again.
Thanks for the help.
Hodag
#10
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What would cause #4 plug to go bad? Faulty plug? Injector going bad?
And... you gapped the plugs to .040" before you put them in, right?
#11
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Best you can do now is reset the ECU and drive it until it throws a code again.
#12
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Best you can do now is reset the ECU and drive it until it throws a code again.
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Thanks for all the input guys. As always this forum has been a great help. I just used it as reference when I did the timing belt, cleaned the MAF, and throttle body. Luckily the 4Runner has been very reliable and I have been able to tackle everything myself. The 3.4 is a little more complicated than the 2F in my FJ60.
I reset the ECU this morning and drove about 15 miles so far with no problems. Seems to start better for sure, and all the other bad symptoms are gone.
Thanks again.
Hodag
I reset the ECU this morning and drove about 15 miles so far with no problems. Seems to start better for sure, and all the other bad symptoms are gone.
Thanks again.
Hodag
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160,000 miles on my wifes 96 4Runner. Already contacted the dealership. They said no recall. Not believing them I contacted Toyota corporate. Corporate said no recall on the engine.
My gasket looks like it had been replaced already and whoever did it put waaaay too much torque on the headbolts.
Good luck with your Runner friend.
Ryan
My gasket looks like it had been replaced already and whoever did it put waaaay too much torque on the headbolts.
Good luck with your Runner friend.
Ryan
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