have a code, 303, number 3 cylinder misfire. I know it is under and behind virtually everything on the engine. I am going to change all three coils in the rear and all plugs on the engine. It just seems to me that with this code there should be other codes, maybe a code for the coil or fuel injector. I am just going to assume that it is the coil and do the complete rear. Should there be other codes? I found a link to a site with instructions, but that site is no longer available (cox). Anyone know where I could get some instructions, although, with a good camera to photograph all the hoses, the rest seems easy, maybe?
I guess what I am asking is with the code saying I have a misfire on cylinder 3, should I also have other codes for maybe coil, or fuel injector? I am just assuming it is the coil. Hate to change the plugs and coil and still have the misfire.
I guess what I am asking is with the code saying I have a misfire on cylinder 3, should I also have other codes for maybe coil, or fuel injector? I am just assuming it is the coil. Hate to change the plugs and coil and still have the misfire.
If it's limited to cylinder 3, think of things exclusive to cylinder 3. Plug, coil, injector, wire to coil. Don't know what other codes you think you should see.
Some questions:
Approximate mileage?
Are there any symptoms, such as engine miss/vibration at idle or high RPM, poor acelleration/dimiinished power, etc.?
Is this vehicle usually driven regularly every day?
Was any service performed just before the problem was noticed?
Have you recently tried a different gasoline brand?
Even though several TN Forum contributors have reported defective ignition coils, you shoud try to rule out a clogged injector before proceeding to pull off the plenum to access the rear bank of spark plugs. You might first try a can of injector cleaner with your next refueling.
A bad coil will often (but not always) store an igniter code in addition to the misfire code.
mileage is about 90,000. No symptons other than a very dirty air filter. It is driven regularly. No service or maintenance done prior. Have not changed brands of gasoline. I do have two new coils and one I recently installed onto no. 2 cylinder, plus six new spark plugs. I plan to change the two rear coils and swap out the newer coil on number 2 to the rear. I also plan to get some good fuel injector cleaner. Would it be wise to swap out the No. 3 fuel injector with the number two injector just in case?
Well . . . none of those answers suggests to me a higher-than-normal likelihood of a clogged injector. I should have also asked at what tank level you usually refuel. The more fuel in the tank, the less chance of moisture and sediment being pumped through tiny injector passages, particularly during Winter months.
It sometimes helps to first review how the misfire detector works:
Input signals from existing sensors are used to calculate crankshaft rotational velocity and acceleration. By comparing the acceleration resulting from each cylinder event, the power produced by each cylinder during its power stroke is inferred. When the power output of a particular cylinder is sufficiently less than a calibrated value, and/or the remaining 5 cylinders, then the suspect cylinder is determined to have misfired. In auto engineering lingo, a misfire is defined as absence of a normal combustion event, due to lack of spark, suitable air-fuel mixture, or compression.
That you have no symptoms is a good sign. If the inferred misfire is bad enough, the powertrain computer may shutdown that cylinder to prevent raw fuel from damaging the catalytic converter. Then you would have an obvoius skip/miss and loss of power.
Unfortunately, there is no easy way I know for the average "DIY mechanic" to determine the specific cause other than running a compression test and swapping parts. And swapping parts is real pain when you have to disassemble and reassemble the top of the engine each time to test results. It could be that one cylinder is a little weak due to something as simple as an oil-fouled plug If it were my Avalon, with 90K "on the clock", my inclination would be to replace all 3 injectors, ignition coils, and spark plugs in that cylinder bank, in the hope I would not have to pull the engine apart ever again.
I recently purchased a set of reconditioned injectors from fuelinjectorwhse.com and installed them in a 1994 Nissan Maxima V6 with a skip. This is a similar deal where the entire intake manifold has to come off. To my surprise, the engine ran better than new after the swap. And much cheaper than OEM injectors.
I will check with your supplier of fuel injectors to see if any are available and how long I have to wait. If the wait it too long I may just swap out the number 3 injector with the number two then do a good fuel injector clean. Don't know what else to do, wife wants her car back. There is a definite missfire because I can feel it in the engine.
inov8 has made another of his usual outstanding contributions.
Let's assume that push comes to shove and you have to tackle that nasty rear bank.
You can google for 2GR-FE info - there are pieces of the factory service manual for that motor if you google. I could provide it here , but this site has an agreemnet with Toyota not to post intellectual property.
That aside - I will tell you there is no way in H you are going to get to the rear spark plugs on a 2GR-Fe motor unless you remove the windshield wiper arms and then the grille that runs horizontally.
I can see you are right about the windshield wiper assembly, it will all have to come out to get to the plenum nuts. Once that is out and the plenum removed, I think it will go quick.
I let my Avalon sit for a little over a month without starting or driving it because of the salt, during that time we had a week or two where it was like 10 - 40 below zero outside almost every day. and when I went to start it two weeks ago it had a very small miss and smoked for about a min or so than would run great tell it sat for more than one day than would do it again for a min or so. I figured it was bad gas so I want and bought a can of SEAFOAM and dumped it into the gas tank. Now it runs excellent again no matter how long it’s been sitting. That may be nothing like your situation but I thought I might share it anyway.
po35x would be the code for a bad coil on cylinder x. It is usually accompanied with codes po301 to po306. So most likely it is not the coil. With that being said, if i went to the trouble to get to that sparkplug you can bet I would change the coil while I was there.
Inspecting the sparkplug may help find the culprit.
I just did mine a couple of days ago. I have the instructions thanks to tn member nov8 and pics if you want. shoot me a pm and I will email them to you if you want.
Thanks for all the replies. I have replaced the coils on the rear bank, also replaced all spark plugs, this narrows it down to the fuel injector. Am in the process of running a second bottle of Lucas Fuel injector cleaner. The only code I have is cylinder misfire on cylinder 3 and also pending code. I noticed yesterday that after clearing the code it does not come back at idle, but comes back when driving. Also noticed that if I am going down a hill the engine light stops flashing and goes out, so it seems that maybe it is only misfiring on acceleration or under a load. So, maybe it is supplying enough fuel at idle, but under a load cannot supply enough fuel, don't know. Have a can of seafoam that will try after the Lucas gas has ran through. The guy at Autozone advised against doing the seafoam while the Lucas was still in the gas. After this I guess I will have to order one of the remanufactured fuel injetors that inov8 mentioned, and also go to Alldata and get a subscription for the Avalon . Any ideas?
I have to agree that compression and fuel delivery are the most likely things left that would impact just one cylinder. This is not a surprise, given the lack of an igniter fault code. Each spark coil contains a circuit that attempts to confirm a spark did actually occur, and reports same back to the powertrain computer via a diagnostic wire. This system is not however, foolproof. The spark can occur within the boot or coil instead of the plug, and the diagnostics will merrily report that all is A-OK.
Once you had the plenum off, you were within 5 bolts and a fuel-line disconnect of removing the fuel rail along with all 6 injectors, so experience should pay off on this pass. The old adage about ounce of prevention being equal to pound of cure applies here. I stuff rags into the intake ports because the injectors and lower injector seals sometimes fall off when withdrawing the fuel rail. And you know where Murphy's law dictates where they will end up.
Toyota recommends replacing all 6 lower seals (they call them vibration isolators) after removing the fuel rail. My guess is there might be a vacuum leak if you choose not to. Toyota also recommends lubricating the injector O-rings with gasoline or spindle oil (I think they mean bearing lubricant, but not sure). I like to use Vasoline. It withstands fuel and high temperatures, and does not attack rubber. Motor oil is not a good choice. The injectors I purchased came with new O-rings already attached.
The throttle body has a coolant passage to prevent venturi icing. I am curious . . . did you drain or partially drain the cooling system as Toyota recommends. or just minimize the leak by plugging the hoses after removal (what I usually do)?
Finally, I don't think there is anything you can get from Alldata that you cannot get from the Toyota Technical Information Center, and Alldata is probably more expensive. PM me if looking for something specific.
Last edited by inov8; 02-10-2012 at 02:55 PM.
Reason: dumb spelling error
looks like I will have to replace the fuel injector for that cylinder, I will purchase from your supplier of rebuilt fuel injectors. I checked the Toyota Information Center but the price is $15 for two days and I think Alldata is about $24 for a whole year. I need some good information on exactly how to change the fuel injectors. The Autozone site is a joke. As for the lower seals, where can I get those or do I need to go to Toyota?
Great posting inov8...I went through the same thing on coil#1. The PITA part was accessing these parts. Yes, you must remove that plastic wiper cover, the wiper motor and the box it sits in, two small bolts that hold down the top intake plenum to the engine (ABS plastic) My Avalon had 70,000 when it happened so, I didn't want to take a chance so I replaced all 3 coils, spark plugs (highly recommend) using anti-seize on your spark plugs..these are aluminum heads and I've seen threads come out with the spark plugs on many cars), the intake gaskets and the breather hose. I kept the remaining 2 working coils and vacuumed-packed them. I didn't go aftermarket since BMD, Beck-Arnely are all made in China.
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