Deep in Mexico and P0304 code arises

layhammer

New member
Hello,

I have a 1998 4x4 4runner with 240,000 miles on it.

I have used this forum for a few years now and typically have found the answers i was looking for here without needing to post. You guys know your stuff.

This time i am in a different situation. I am in Chiapas Mexico and i speak mediocre spanish. My problem started with a check engine light back in San Diego. I would get a stutter between 1500-2100 RPMs only while in overdrive. I got the code P0120(faulty TPS) and handled the repair. After a few weeks on the road, i began to get the stutter again. I read up on the issue and finally decided to replace the spark plugs. They have an Autozone down here and i tried to get NGKs, but they only had Bosch and a few other brands. I bought the best ones they had, dual ground Platinum 2+, and had them replaced since my tools are back at home. I drove away and the vehicle felt fine until i began going up a very steep grade for about 1 minute at which time the vehicle started to misfire. The check engine started to blink only when the vehicle downshifted to make it up the hill. I pulled out my code reader and got a P0304(cyl 4 misfire). Back to the shop. After 4 hours of them testing, they could not figure out the problem. We were headed for Guatemala and now are stuck in Chiapas until i get this issue handled. Any advice would be greatly appreciated.
 
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I am interested in hearing more on what other causes of this problem might be. I just got a new to me 96 4runner with 120k and have been having this same recuring issue except with cyl # 5.

I had a tune-up and the plugs replaced, then had to bring it back and had the ignition wires replaced. I am no longer getting occasional misfires and loss of power, but I still have a slightly rough idle (especially once it has warmed up) and the check engine light just came on again.

To top it all off I have another 10 day work shift driving around on crazy roads in the middle of nowhere and my mechanic cannot squeeze me in before I have to leave.

Thanks in advance for your answers. This forum helped me choose a 4runner for my work vehicle and aside from this issue it has been working out great so far.
 
Yikes, man down in Mexico!

Make sure your spark plug wires are pairing your cylinders correctly. If you are standing in front looking at the engine, the cylinders are numbered...
Firewall
5 6
3 4
1 2
Grille
...and paired by the wires as 1-4, 3-6, 5-2.

Good luck.
 
To start. Causes:

Process of elimination. Lets eliminate what we can right off the bat and dive into some detail tomorrow.

Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
Poor compression
Defective computer
 
Last edited:
Sounds like to me what happened with my Tacoma. Everyone told me it was spark plugs and wires so I replaced those, still had the misfire. Next they told me it was a coil pack so I swapped the coil packs around and still the same thing. I had a feeling it was the injector so I replaced the injector and never had a misfire again. Good luck man
 

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