99 4Runner with a 304 code

T

Twams

New member
99 4Runner. If we step on the gas it stutters and shakes. The engine light is on and if we step the gas down sometimes the engine light will flash. The code was 304 (Cylinder misfire #4) Is there any easy test to see what it is before i start replacing plugs, wires and coil. It also said it could be a vacuum leak or Injector fault. Thanks for any help.

Tom
 
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Easiest thing to do first is pull #4 plug and look at it and the wire. If you have carbon tracking down the white body of the plug, replace the plugs and wires. More than likely you will find a bad plug or injector. Unfortunately #4 injector is the only injector you cant get any access to without pulling the plenum. If the plugs and wires check out ok, pull the plenum, remove #4 injector and switch it with #1 injector. If the miss follows to #1, you know you have a bad injector. Use a silicon based lube on the orings to avoid pinching and leakage
 
Thanks, I checked the plug and it appeared to have a carbon stripe. I bought a set of Bosch +2 and installed the three on that side. I also switched the Coil pack with #2. The truck ran much better but still missed a little. I plan on going to Autozone and check the code again to see if the code change. Any thing else i should do at this time?
 
most helpful diagnosis steps

I am following along but have no troubles at present.

This is really helpful toytech76 to see the steps of the diagnosis.

Twams I hope this takes care of the problem for you, post up what all you learn please so we can all benefit.
 
Still it is still running bad. I reset the Check engine and drove around but the check engine only came on once and went off. i was accellerating and flashed but did not stay on. Is that enough to get a code? or does it need to be on all the time to read the code?
 
Ok. The Code is still 304. So i will change the injectors. Do they come out easy or do i need any special tools. Also can they be cleaned or should i replace it if it comes up bad.
 
Thanks for all the help. If i was a little brighter the problem would have been solved sooner. I took it that the plug wire # was for the cylinder that was at the end of the wire. After i decided to install the other 3 plugs i figured out i saw the number on plug wire were strainge with #3 in the back.

The #4 had a definate carbon strip and so far it runs Great.

Thanks Toytech!!!
 
So you were looking at the wrong plug at first, and then once you found the correct plug, you just replaced it and its all gravy?

Just asking for learning purposes.
 
so just the one plug was actually bad?

just trying to summarize for the mechanically impaired-it ended up being just the one plug was bad?

Also I have heard various figures for the spark plugs-is 30K miles really about all they should last?
 
Re: so just the one plug was actually bad?

Ron Helmuth said:
just trying to summarize for the mechanically impaired-it ended up being just the one plug was bad?

Also I have heard various figures for the spark plugs-is 30K miles really about all they should last?
Click to expand...
Yes. The standard plugs are good for 30K, platnum plugs are 60K and iridium plugs range from about 100-120K depending on application.
 
thanks very much toytech76

probably time to check mine again.

I see you recommend the dual electrode NGK or Nippodensos.

Time for me to start learning more about plugs.
 
read my mind

thanks- I was trying not to ask

I wish I were closer to you toytech76- I think you could be doing a lot of work on my ride!

I certainly learn a lot from you and that is the best kind of repair for me-when I can learn how to do it myself the next time.

Appreciate having you around, thanks.
 
I appreciate that! Im always glad to help anyone out. I agree it would be nice to have you and many others closer to me. I could quit my job and just work from home!. lol
 
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