swiller429

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-ge...ml#post1469073 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.

waypoint

Not sure where you got your rebuilt injector, but I bought a set from injectorwarehouse.com last year that turned out to be pure junk. Made my truck run worse, and when I finally pulled them for testing 2 of them were dribblers...didn't seal when closed and were dumping raw gas into their cylinders.

swiller429

The injector I got was from GB remanufacturing

Whitfield

If you would prefer to not spend extra $$$ replacing parts then you can move the suspect part to an alternate location. If the problem follow the part then you have your answer. Replace the part. Some folks don't mind feeding their truck a stack of new parts while trouble shooting... But me, I've got more than a few and can't feed them all like that.

Building a set up to bench test injectors on the rail making a 3x gas shooting flame thrower to test pattern and function is awesome too.


Last set I played with ~ I put a can of sea foam in Wifey's ultra sonic jewelry bath and was cycling the injector with a 9v battery.

swiller429

Thats what I ended up doing yesterday. I switched the 3 injector with cylinder 1 and no surprise, the problem jumped.
I was pulling codes p0306, 303, 302, and p0171 right before I swapped the injector. I am hoping that all those codes were just as a result of the one bad injector throwing everything else off.

waypoint

Sorry to hear it, but at least you're making progress. I ended up buying a factory set from a junkyard and having Witchdoctor clean and flow-test them. They arrived with all new o-rings, insulators, and filter baskets installed and ready to go. Cheaper than new OEM, and with so much knockoff junk floating around the "rebuilt" market it was the best option I could find.

Ladythump

I'm having the same problem, can i ask about how much a garage will charge to replace my 6th injector?

I have 244K on my 99Runner and never had the injectors changed. If they have to replace one, would it be a good idea to replace all of them while they are at it or should I just wait til others fail??

dontblink10

I am very interested to hear the answer to Ladythump's question myself...

My #3 injector is bad. I've ordered one OEM injector at $157 and hope to not need to do all 6 at once.

Also, what parts other than the injector itself, insulator, and injector O-rings did you guys have to replace? Did you replace the "union bolt gaskets" as well that are on the ends of the fuel supply rail? Did you replace the throttle body gaskets (side and bottom) when you replaced your injector(s)?