The other day, my CEL and VSC off & trac lights came on so I went to Autozone to get a readout of what the problem is since they offer free obdII scans. I figured I'd do this before I take it to Toyota so I know for myself. Well it turns out that there is multiple cyclinder misfire, especially in cylinder 7. Now my question is, what can cause a cylinder misfire? What can fix it (replacing spark plug wires, coils, etc)? Ironically, there were no readouts on why the VSC lights came on. Anyways the car is being dropped off Friday for an oil change and I'll have them look at the CEL and VSC problem and see what they "claim". FYI the engine has 75,200 miles on it and the last major tuneup I had was in June 2005.
The other day, my CEL and VSC off & trac lights came on so I went to Autozone to get a readout of what the problem is since they offer free obdII scans. I figured I'd do this before I take it to Toyota so I know for myself. Well it turns out that there is multiple cyclinder misfire, especially in cylinder 7. Now my question is, what can cause a cylinder misfire? What can fix it (replacing spark plug wires, coils, etc)? Ironically, there were no readouts on why the VSC lights came on. Anyways the car is being dropped off Friday for an oil change and I'll have them look at the CEL and VSC problem and see what they "claim". FYI the engine has 75,200 miles on it and the last major tuneup I had was in June 2005.
Ahhh alllllottt of things can cause a cylinder misfire. Having the code would be helpful. If they didnt change the plugs at the last tuneup my first guess would be that it is with those. Second guess is that on the ends of the Spark plugs there are little metal caps that connect to the spark plugs wires. If these come loose then there is a weak connectiong between the wires and the plug. I would pull the plug and try tightening the gaps lightly with some pliers.
Lets hope its one of these problems! other things can get mroe expensive
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I wasn't able to write down the actual codes when he told me but from what I searched online, it was the P0300 & P0307.
Thanks Gary, I too hope its one of those small problems. They should have changed the sparkplugs on the last tuneup, however whether they actually did that or not, I am not sure.
Wow ok, just spoke with Toyota a few mins ago, they said that its the fuel injectors thats causing the misfiring and the codes are P0300, P0301, P0303, P0307. So 3 fuel injectors need to be replaced and the total will come out to be just a little over $800!!! The fuel injectors are about $176 a piece and the rest is labor. Does this sound right to anyone? And of course, the parts are never in so they will be ordered today and will be in Monday. They also said the switched out the coils and they were fine so that wasn't the case.
Furthermore, they said that the cause of this could have been the aftermarket chip (unichip) I had and I told them that its impossible because the last time the chip was in was back in June and I never got a CEL during the time the chip was in. I think they're just saying that because they can't figure out an actual cause and the fact that the unichip harness was still there (I left it in incase if I ever used the chip again). What concerns me is that how 3 fuel injectors could have failed simultaneously.
Bump! Anyone have any idea how 3 fuel injectors could fail simultaneously? Has anyone had thier fuel injectors replaced because of failure under 90,000 miles?
I'm hoping you can help, as I have the exact same problem, 2001 toyota sequoia SR5 with 75k miles on it, and all of a sudden, i got three misfires, OBD confirmed it
Address 10 (Engine): 4 Faults Found:
P0300 - Random/Multiple Cylinder Misfire Detected
P0303 - Cylinder 3: Misfire Detected
P0305 - Cylinder 5: Misfire Detected
P0307 - Cylinder 7: Misfire Detected
heres more details.. 01 SR5 with 3 misfire codes - Toyota Forums :: Toyota Nation
what did you end up doing? were the injectors really bad?
the only maintenance I havent done is the fuel filter - i went to toyota to pick up a box of parts (for a customer's car) and asked if they had the fuel filter in stock, the service manager told me they dont stock it because they dont even replace them unless the car has over 200k or the lines are rusted but at 60k they do NOT REPLACE THE FILTER... even though they charge for it....
I'd question whether three fuel injectors failed at the same time. I was getting a random engine misfire on my 6 cyl with cylinders 3 & 5. It was driving me crazy. The local Tojo dealer diagnosed a bad coil. They replaced it and a few months later it started doing it again. My scanner showed it to be the same cylinders. I picked up an ohm meter and checked resistance on the replacement coil and it was within specs. I checked the bad one per Toyota and it was also in spec. I should've taken it back and demanded a refund. After talking to a mechanic friend, he said check the caps on the plugs, it was loose on cylinder three. Who the hell puts aluminum caps on a steel post? Denso apparently does. Continued to have problems with the cap coming loose due to heat expansion. I've since changed plugs and the problem has been gone for awhile. An ohm meter is the primary tool they'll use to chase down the problem. With your injectors, ask them if that's how they diagnosed. If you have them changed, I'd definitely check them myself afterwards and then go raise heck if they're still in spec. Chasing electrical problems suck...
^^^ I would agree. The most common issue would be a bad coil, bad plug wires, or bad plugs. Coukd be a whole host of other problems, but most likely a coil issue.
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First I checked the system with these instructions:
Step 1 Turn the Tundra's ignition to the "On" position. Use a voltmeter to test for battery voltage at the ignition coil's positive terminal. Check the camshaft and crankshaft position sensors if there is voltage.
Step 2 Detach the connector to the camshaft position sensor. Measure the resistance between the terminals with an ohmmeter, which should be 835 to 1,400 ohms on a cold engine and 1,060 to 16,45 ohms on a hot one.
Step 3 Unplug the crankshaft position sensor connector and measure the resistance between its terminals. It should be 1,630 to 2,740 ohms for a cold engine or 2,065 to 3,225 ohms for a hot one.
Everything was in spec.
I pulled the plugs, 4 were okay,1 was really orange, 2 were poor with a burnt off electrode, 1 had a green hue to it (wtf?).
i also checked the air filter- fine, and sprayed the MAF with some cleaner.
I noticed the rubber grommet at the end of the #7 coil was very orange and more rigid than the others, but the resistance was within spec.
Replaced the plugs with some platinum NGKs, re-gaped to .031, car runs fine, purrs at idle, no hesitation. No CELs, logging the performance on the computer, all cylinders running equal, O2s reading clean.. Problem solved?
Its not as cold out today as it was last week, but that should have taken care of it now.
thank you for all the help, I'm sure it will come in handy in the future.
Another thing you could do is switch the coil pack with one of the other ones,
after clearing the code of course, and see if it throws a code for the cylinder
you connected it to.
John
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You're right, but switching the coil when its a multiple misfire might make things a bit complicated. I've been advised to order the part from a local store like Advance Auto and if it fixes the problem, great, if not return it, its covered under their 30 day policy.
Another cause could be a blown head gasket, especially in the case with
adjacent cylinders misfiring. Hope all works out for you and that isn't
the problem. Sounds like you had some funky plugs so maybe that's it.
John
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yea the misfire has been gone since i did the plugs, though the plus really didnt look that bad (my 87 toyota ran fine and i pulled the plugs at 175k miles, those were some bad plugs..yes, original).
but the car still has a weird idle... it only happened once since, I think I jsut have to clean the TB and IAC..
the headgasket? really? i think thats a bit of a stretch, i see your reasoning since they are adjacent cylinders, butwith good compression and clean fluids i ruled that out quickly.
What can cause a cylinder misfire?
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The fuel injectors are about $176 a piece and the rest is labor. 
Does this sound right to anyone? And of course, the parts are never in so they will be ordered today and will be in Monday. They also said the switched out the coils and they were fine so that wasn't the case.
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