swiller429
New member
So I have a 1999 4runner 3.4L limited with 150,000 miles. Recently I started having problems with cylinder misfires. The first day it happened I immediately read the codes and pulled up the codes p0300, p0303, p0305, p0306, so that is multiple engine misfire, specifically cylinders 3, 5 and 6. After this I did the obvious thing and replaced the spark plugs. This fixed the p0305 problem but the 303 and 306 remained. This basically results in the car shaking while idle and at higher speeds (45+).
With the 303 and 306 firing on the same coil pack, I did the obvious thing and replaced the coil pack. No change. But I know that often times there can be problems with the coil packs not making good contact to the plugs or the 12 volt connection not making good contact so I fiddled around with the connections for about an hour or two to make sure everything was connected properly. Still no change.
After reading multiple posts exactly like this one I concluded that it must be the fuel injector. It didn't seem right to me but all the symptoms seem to have been there and after looking at this post http://www.toyota-4runner.org/3rd-gen-t4rs/149634-p0300-p0302-p0305-my-experience-finally-fixed.html#post1469073 it seemed like this would be the solution. So I replaced the #3 fuel injector with a re-manufactured part. This solved the p0303 (at least for a day or two) but I still was showing p0306.
With the 306 I checked the spark plug cables and found out that the boot had been ripped and the spark was arcing out. So I replaced all three cables.
The car ran well for about 2 days and then It started shaking and throwing up p0303 and p0306 again. However this time it was a new pattern. Now the car would run fine if it had not been driven for a couple hours but if the car is started warm, it misfires. After searching this symptom I found out that it is pretty characteristic of a bad injector. However, since I just paid $45 bucks for a new one, I figured I would at least try and test it out.
I did the "screwdriver test" first and heard that the #3 injector was clicking much quicker than the #1 injector. This peaked my curiosity so I decided to do a resistance test and these where my results.
So that is the extend to which I have fiddled with this car. My suspicions are that I might have just gotten a bad fuel injector or that the wiring at some point along the way is bad. (I did see some mouse droppings on my engine so I was wondering if they might have done some damage. who knows.)
Any ideas or information would be great! I am pretty committed to not taking it to the shop because honestly, I don't know what they would do that I haven't already done.
With the 303 and 306 firing on the same coil pack, I did the obvious thing and replaced the coil pack. No change. But I know that often times there can be problems with the coil packs not making good contact to the plugs or the 12 volt connection not making good contact so I fiddled around with the connections for about an hour or two to make sure everything was connected properly. Still no change.
After reading multiple posts exactly like this one I concluded that it must be the fuel injector. It didn't seem right to me but all the symptoms seem to have been there and after looking at this post http://www.toyota-4runner.org/3rd-gen-t4rs/149634-p0300-p0302-p0305-my-experience-finally-fixed.html#post1469073 it seemed like this would be the solution. So I replaced the #3 fuel injector with a re-manufactured part. This solved the p0303 (at least for a day or two) but I still was showing p0306.
With the 306 I checked the spark plug cables and found out that the boot had been ripped and the spark was arcing out. So I replaced all three cables.
The car ran well for about 2 days and then It started shaking and throwing up p0303 and p0306 again. However this time it was a new pattern. Now the car would run fine if it had not been driven for a couple hours but if the car is started warm, it misfires. After searching this symptom I found out that it is pretty characteristic of a bad injector. However, since I just paid $45 bucks for a new one, I figured I would at least try and test it out.
I did the "screwdriver test" first and heard that the #3 injector was clicking much quicker than the #1 injector. This peaked my curiosity so I decided to do a resistance test and these where my results.
#1 injector = approx 15 ohms
old #3 injector = approx 14 ohms
new #3 injector = approx 15.
So that is the extend to which I have fiddled with this car. My suspicions are that I might have just gotten a bad fuel injector or that the wiring at some point along the way is bad. (I did see some mouse droppings on my engine so I was wondering if they might have done some damage. who knows.)
Any ideas or information would be great! I am pretty committed to not taking it to the shop because honestly, I don't know what they would do that I haven't already done.
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