Pls Help: Acura MDX Chk Eng (misfire)
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Pls Help: Acura MDX Chk Eng (misfire)
I have a 2003 MDX and the Honda dealer cannot figure out what's going on. 117,000 miles. Replaced spark plugs this summer. Check engine light comes on sometimes when I start the car, does NOT flash, but stays on entire trip. It will come on for a few days then go off for a few days. Unpredictable. Codes are always the same, 7 codes all misfires P300-306. This past week additional lights came on (ABS, !, VSA) together. Dealer clears all the codes then they come back within days. Not related to the gas cap issue that can happen.There is nothing noticeably wrong with the car when I drive it. Doesn't rev, shake, make noise... nothing. I would think everything was just normal if the lights weren't on.
The dealer wouldn't say what the code info was that they read, but they said the system said something about "low voltage" but they didn't really know why. They tested the battery and it was fine.
I think they want me to replace the ignition thing tomorrow but I'm concerned about spending money on things that may not be needed.
Not sure if any of the following could be related, but figured I'd mention them to be thorough:
- We got a camper that we tow with my MDX. It is only 2400lbs. We've only pulled it about 4 times, but the engine light started after the first time towing.
- The lights started not to long (within weeks) of having an issue with my shifting. We ran over a dead deer and it knocked something loose. The dealer had to replace a pin in the shift thing (that's my technical term for it!). That fixed the issue. The shift was able to move out of park without the key in the ignition. I was even able to turn the car off and take out the key while it was still in drive. Like I said, replacing the pin thing fixed it.
PLEASE help! I'm so skeptical that they'll try to rip me off, it's happened so many times. They must see a big target with a young woman walking in by herself! I LOVE my car and just want to keep it going great!!!
Last edited by Heatherjo811; Jan 27, 2010 at 07:46 PM. Reason: provide additional details
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Re: Pls Help: Acura MDX Chk Eng (misfire)
UPDATE: The dealer today retested the battery and said sometimes it showed okay and other times bad so they replaced it. The CEL light hasn't come back on yet today. The ABS / ! / VSA the dealers said was unrelated. They said those are coming on and off because my ABS modulator is going bad. $1400 to replace it. They said I didn't have to replace it, brakes would work fine just no ABS. Those 3 lights were off when I left the dealer and stayed off through 2 more trips but came back on tonight in the midst of driving down a residential road with no prompting. UGH.
$cat /dev/urandom
Joined: Feb 2005
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From: Thornton, colorado, usa
Re: Pls Help: Acura MDX Chk Eng (misfire)
What spark plugs were used to replace the old ones? were they honda dealer installed?
Here is why I ask. It seems more and more lately, a lot of manufacturers are using special long life iridium spark plugs that have different resistance than some of the cheaper, less long life style that are available at autozone and the like. I have read that the newer kind need 4,000-6,000 fewer volts to spark, and new ignitions are designed to provide the lower voltage. The next issue is the less long life spark plugs are $14/plug cheaper than the ones you probably should be using, creating a great financial incentive for inexperienced users to replace their plugs with the wrong ones to save a buck, or $75.
My experience with that is exactly the same on an '06 accord I worked on. guy brought it to me with the same misfire issue, code 304 or 303, a couple of those, and was all worried. I did a lot of diagnostic on my own time, only for him to reveal that he bought some cheap spark plugs and installed them himself, probably also without a torque wrench. that got me to wondering if something as simple as that was the cause, so i had him shell out $19/plug from honda, and lo and behold, no more CEL.
Moral of the story is if you used the cheap spark plugs, and i don't blame you, then that may be causing your issue with the ignition.
the ABS modulator sounds like BS to me, as there are ABS sensors in each individual wheel that could be messed up by hitting a deer carcass. I would be testing each individual one to determine if any of them are bad before shelling out $1400 for a new modulator, which will then still receive bad input from the smaller, cheaper sensors downstream, and not solve the problem.
good luck.
Here is why I ask. It seems more and more lately, a lot of manufacturers are using special long life iridium spark plugs that have different resistance than some of the cheaper, less long life style that are available at autozone and the like. I have read that the newer kind need 4,000-6,000 fewer volts to spark, and new ignitions are designed to provide the lower voltage. The next issue is the less long life spark plugs are $14/plug cheaper than the ones you probably should be using, creating a great financial incentive for inexperienced users to replace their plugs with the wrong ones to save a buck, or $75.
My experience with that is exactly the same on an '06 accord I worked on. guy brought it to me with the same misfire issue, code 304 or 303, a couple of those, and was all worried. I did a lot of diagnostic on my own time, only for him to reveal that he bought some cheap spark plugs and installed them himself, probably also without a torque wrench. that got me to wondering if something as simple as that was the cause, so i had him shell out $19/plug from honda, and lo and behold, no more CEL.
Moral of the story is if you used the cheap spark plugs, and i don't blame you, then that may be causing your issue with the ignition.
the ABS modulator sounds like BS to me, as there are ABS sensors in each individual wheel that could be messed up by hitting a deer carcass. I would be testing each individual one to determine if any of them are bad before shelling out $1400 for a new modulator, which will then still receive bad input from the smaller, cheaper sensors downstream, and not solve the problem.
good luck.
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Joined: Jan 2009
Posts: 8
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From: NEW ENGLAND
Re: Pls Help: Acura MDX Chk Eng (misfire)
What spark plugs were used to replace the old ones? were they honda dealer installed?
Here is why I ask. It seems more and more lately, a lot of manufacturers are using special long life iridium spark plugs that have different resistance than some of the cheaper, less long life style that are available at autozone and the like. I have read that the newer kind need 4,000-6,000 fewer volts to spark, and new ignitions are designed to provide the lower voltage. The next issue is the less long life spark plugs are $14/plug cheaper than the ones you probably should be using, creating a great financial incentive for inexperienced users to replace their plugs with the wrong ones to save a buck, or $75.
My experience with that is exactly the same on an '06 accord I worked on. guy brought it to me with the same misfire issue, code 304 or 303, a couple of those, and was all worried. I did a lot of diagnostic on my own time, only for him to reveal that he bought some cheap spark plugs and installed them himself, probably also without a torque wrench. that got me to wondering if something as simple as that was the cause, so i had him shell out $19/plug from honda, and lo and behold, no more CEL.
Moral of the story is if you used the cheap spark plugs, and i don't blame you, then that may be causing your issue with the ignition.
the ABS modulator sounds like BS to me, as there are ABS sensors in each individual wheel that could be messed up by hitting a deer carcass. I would be testing each individual one to determine if any of them are bad before shelling out $1400 for a new modulator, which will then still receive bad input from the smaller, cheaper sensors downstream, and not solve the problem.
good luck.
Here is why I ask. It seems more and more lately, a lot of manufacturers are using special long life iridium spark plugs that have different resistance than some of the cheaper, less long life style that are available at autozone and the like. I have read that the newer kind need 4,000-6,000 fewer volts to spark, and new ignitions are designed to provide the lower voltage. The next issue is the less long life spark plugs are $14/plug cheaper than the ones you probably should be using, creating a great financial incentive for inexperienced users to replace their plugs with the wrong ones to save a buck, or $75.
My experience with that is exactly the same on an '06 accord I worked on. guy brought it to me with the same misfire issue, code 304 or 303, a couple of those, and was all worried. I did a lot of diagnostic on my own time, only for him to reveal that he bought some cheap spark plugs and installed them himself, probably also without a torque wrench. that got me to wondering if something as simple as that was the cause, so i had him shell out $19/plug from honda, and lo and behold, no more CEL.
Moral of the story is if you used the cheap spark plugs, and i don't blame you, then that may be causing your issue with the ignition.
the ABS modulator sounds like BS to me, as there are ABS sensors in each individual wheel that could be messed up by hitting a deer carcass. I would be testing each individual one to determine if any of them are bad before shelling out $1400 for a new modulator, which will then still receive bad input from the smaller, cheaper sensors downstream, and not solve the problem.
good luck.
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