Hello all. It's my 00 4runner with the 3.4 6 and I keep getting the p0303 code. I have so far replaced all the spark plugs, wires and boots and a new coil pack on cylinder 3. Seafoamed the engine and Lucas for the gas tank twice already. Still it's messing with me with this misfire that only happens when the motor is warmed up after driving around town and not when it's cold. EVERY once in a while it will go to missing when I first get in it in the morning. But hardly ever. I have tested the fuel injectors on the passenger side.

#1 14.3 #3 15.7 #5 14.3. So far I have no idea what to even look for after this. Anyone else having these issues??

 

How did you test the injectors? Just a resistance check or acoustic check or both is no guarantee of a good injector. I would swap the injector with another and see if the problem moves. If you are positive it is not an injector, then a compression check is your next step. What does the plug look like on Cyl 3? Any sign of unburnt fuel?

 

The compression test averaged 200 psi on the passenger side and 210 for the driver side. I did just a resistance test on them and I guess are within that 14 to 18 Ohms that I've read on other forums that it's supposed to be in. I will be swapping out the #3 and #1 injector and replacing the coolant temp sensor today hopefully. Ha ha. This is a stupid problem to have.

If this doesn't work today then only thing I can think of left would be either a leaking lower intake manifold or a burned valve.

 

I had similar problem but in case it was cylinder # 5 i switch coils spark plugs and nothing change i listen to injectors to see if they all saound the same and # dint sound the same so what i did i swap them to # 1 and it follow the miss to #1 now so i guess i need a new injector! I was thinking the worse been a burn valve or something but i was lucky. Good luck with your rig

 

Strange it is only one cylinder., Had a similar issue on my 22RE full injected, long long story, ended up replacing gas tank as it had rust in it and was clogging electric fuel pump inlet screen. This also caused a fuel injector problem which had to be replaced.
Worth checking the screen on the full pump to see if it is clogged.

 

turns out it was the injector that was faulty. stupid moment for me and learned the hard way was when replacing it ha ha ha use a little motor oil on the O rings. had to take it all apart twice because I put them in dry. lol

 

Where did u got the new injector from? Im going to need one too

 

I went to autozone to get it. think it was $125 for it. when you take the fuel rail apart you'll need to take the top bolts off the timing belt cover and mover the clamp backwards from the water hose. don't need to take it off. you can get to te banjo bolt on the passenger rail and loosen the drivers side fuel rail banjo bolt. move that out of the way then take the rear fuel line off the rail and take the rest apart from there.

be sure to get a new O ring kit incase you need to change a few old ones out. belive me. lol. nothing makes you more pissed at yourself than thinking all is good and you've got gas spraying out of a bad o ring lol.

 

Rockauto has the best prices for remanufactured OEM injectors. $39 w/ $10 core.

http://www.rockauto.com/?carcode=1364723&parttype=6224

 

R u talking about to remove all injectors you got to do this? Cause when i swap my injector from # 5 to # 1 i dint have to do all that. Other thing i notice is that the new injector comes with new o-rings but i think what i mean is that if i remove one injector i need to replace all o-rings or msybe yet replace all injectors, but you are talking about more then $600 bucks for all of them and i already got to but other stuff for my new rig so i might have to hold on to that lucky that is only one that is missing by now.

 

Johnboy80, Glad you got the problem solved. I ended up having to pull my whole feel injection /intake assembly off 4 times to replace. Got to where i could do it in 20 minutes.
If anyone else has fuel injection problems that reoccur, I would (894runner) pull fuel pump from gas tank (under passed her seat rear, not that hard), check screen/strainer to see if it is clogged. Also do a visual n gas tank. If it is rusty replace it, feel filter and blow the line out. Until I did this the problem kept reoccurring. Especially when the tank was run low on gas.Unfortunately 2 weeks after doing this with truck running great , My son totaled it. Parting it out.

 

Damn that sucks big time! Planing or buy another one?