HELP!! P304 Code/Cant Pass emissions

So, after replacing spark plug wires and cables and clearing the check engine light. The light came back on and I'm getting the P304 code again. My question is whether the check engine light can turn off after a week of driving with the new plugs and cables?

Thanks for any help!

 

Sometimes they do, but when my O2 sensors went out, I just took the terminals off the battery for 15 mins. to reset to ECU. No more Check Engine light, and took it immediately to get my inspection sticker. But it always will come back on unless you correct the problem.

 

If they check the ready status monitors by doing a computer scan you can't do that.

 

Ditto.
Won't work in California unless all of the monitors have passed clear.
Not too often you can just reset and pass... maybe some hick towns where the inspector is just looking for a light, in which case a piece of tape would make it pass

P304 should be cylinder #4 misfire. If the plugs have been changed, then it's elsewhere in the ignition system.

 

Seems this is going to get a bit more expensive. When do you decide to sell or repair??? Thanks for your input..

 

It's worthless i'll give you $100.00 for it.,I'm kidding. It may as simple as a cap or as serious as the motor. Have you considered just paying a shop to diagnose it?

 

Going to shop Wednesday.

 

+1. A P0304 is hardly a reason to sell unless you were planning to trade it in soon anyways.
Depending on mileage/condition, an extracab V6 4x4 with 150k on it is worth $4-5k.

 

Could be a coil if you've done plugs and wires. That's what I'd try. Maybe swap coils and see if the misfire moves.

 

A friend did this on his Audi recently. Swapped coils with one of the other cylinders, reset the computer, and the code moved to the other cylinder. At that point he KNEW what was wrong. No more guessing. Good stuff.

If you can't figure it out, make sure you check the compression also. I hope that's not it, but have to check the expensive stuff too.

My boss had a 3.4 4runner that had one fuel injector fail and cause a miss and trouble code. I'm not sure how the mechanic diagnosed it, but I know it took them awhile. Once they knew what was wrong it was fixed quickly and no more issues.

 

i don't think the 97 has individual coils. The OP stated he replaced "plug wires" so i'm assuming it has a distributor. Parts for the 4 cyl also shows a distributor cap which is a possibility. But if it did have COP ignition yeah you could move them.

Anyway good luck damionseacat. Keep us posted when you find out what it is.

 

Thanks for the assistance guys

 

That narrows it down since a bad coil would generate two P030x codes.

 

Fuel injector on #4 needs to be replaced.