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So this infamous multiple misfire crap has me on the verge of getting rid of the car. Car has 167k miles on it, so still "has time" and what's weird is when I cruise, I get NO misfires. My mechanic connected his "expensive" OBD interface and saw too there are absolutely no misfires when cruising.

So yeah, I did everything below and STILL have the misfire, mostly while accelerating and at idle...

Made sure the replacements were all OEM parts too, smh.

Spark plugs
Coils
PCV valve
Intake hose (had a small crack)
MAF sensor
Idle Control Valve
EGR Valve
Timing belt change with water pump, tensioner, etc.
Valve adjustment
Fuel Injectors

Also,

Cleaned EGR ports and throttle body
Did seafoam through vacuum hose and gas (separately)

Mechanic checked the pressure of the fuel pump and he said it was fine.

Misfire for cylinders 1, 2, 4, 6 is what I normally get. Even though they are all new plugs and coils, still tried changing it around, same misfire codes.

I've legit searched through this whole forum, but no luck 馃槕
@Tonio,
Have you checked your front end suspension? Anything that causes front end vibrations can cause the computer to go apeshit. I had the same thing going on and a mechanic friend told me that little secret. Sure enough I bought a front end kit and the misfire codes stopped.
When any of the front end suspension starts to go or something just fails they cause your front end to vibrate at low speeds, the vehicle's computer can sense the but not identify the actual problem so it gets confused and uses a fully automatic flare launcher to start sending up flares to let you know there's a problem. Any auto parts store can clear the codes out for you for free, they'll come back, but they can be cleared out.
If your vehicle is out of it's warranty you don't need to worry about paying the price for OEM parts, you do need quality parts, but very few actually need to be OEM. Any seals and gaskets you definitely want to keep OEM but the vast majority of everything else can be aftermarket. My front end suspension kit cost about $80 and all the parts have a 10 year warranty, and I put it on myself.
 

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monitor voltage while driving, a bad battery/alternator/battery cables can cause a similar issue. I wouldn't be surprised if the voltage is fluctuating a ton. Also have you checked the knock sensor for damage? Mice can chew the wire and cause all sorts of issues.
 

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Keep in mind with the diagnostics being done: Just because a system/sensor is sending a value/signal that is within spec range, doesn't mean it is sending the 'correct' value/signal. Specifically this comes to mind with the Cat sensors, the could be reading rich, when it is really lean. Both are accurate readings, but maybe not the correct one. Point being, when the mechanic is doing real time diagnostics and it is not showing errors being thrown, have him assess whether the values being sent make sense together.
 
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Discussion Starter #25
Awesome tip! I actually changed bank 1 sensor 1 during the process, it wasn't OEM, may have to get an OEM one, so I'll def have my mechanic check them all out. Thanks 馃

Keep in mind with the diagnostics being done: Just because a system/sensor is sending a value/signal that is within spec range, doesn't mean it is sending the 'correct' value/signal. Specifically this comes to mind with the Cat sensors, the could be reading rich, when it is really lean. Both are accurate readings, but maybe not the correct one. Point being, when the mechanic is doing real time diagnostics and it is not showing errors being thrown, have him assess whether the values being sent make sense together.
 

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Discussion Starter #26
Thanks for the tips man...I checked that first when I started on the "project" 3 months ago, but now that you say that, the terminals I had gotten are shitty, if I force it up, it comes off the battery terminal...I'll check it out.

I'll check out the knock sensor tomorrow, thanks again.

monitor voltage while driving, a bad battery/alternator/battery cables can cause a similar issue. I wouldn't be surprised if the voltage is fluctuating a ton. Also have you checked the knock sensor for damage? Mice can chew the wire and cause all sorts of issues.
 

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Discussion Starter #27
Interesting. I had them changed when I bought the car a few years ago, but I'll have to check them out again. I know my front and rear engine mounts are shot...lol

@Tonio,
Have you checked your front end suspension? Anything that causes front end vibrations can cause the computer to go apeshit. I had the same thing going on and a mechanic friend told me that little secret. Sure enough I bought a front end kit and the misfire codes stopped.
When any of the front end suspension starts to go or something just fails they cause your front end to vibrate at low speeds, the vehicle's computer can sense the but not identify the actual problem so it gets confused and uses a fully automatic flare launcher to start sending up flares to let you know there's a problem. Any auto parts store can clear the codes out for you for free, they'll come back, but they can be cleared out.
If your vehicle is out of it's warranty you don't need to worry about paying the price for OEM parts, you do need quality parts, but very few actually need to be OEM. Any seals and gaskets you definitely want to keep OEM but the vast majority of everything else can be aftermarket. My front end suspension kit cost about $80 and all the parts have a 10 year warranty, and I put it on myself.
 

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I bought Satan's old MDX so I've gotten a bit good at working on it, lol. It's also a 2005 so it's not worth it to me to actually take it to the dealership unless I absolutely have to. There are also very few true mechanics left at dealerships, most are an Acura tech at some level which typically means they're dependent on computers to tell them the problem. When it came to the suspension I took it in and paid to have the car checked out top to bottom and they said other than an oil leak it was fine. The codes kept coming ,and they were always misfire codes. When I noticed how inexpensive the suspension kits were, I decided to give it a shot. Don't forget there are several arms, braces, air rods and bearings on each side. The car was completely out of square/balance the front end was forced up and out so much so that they had 3 different people reset the alignment machine to make sure that they were really that far out.
 

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Discussion Starter #29
Satans MDX lmao! Legit how I've been feeling lately. I love this damn MDX, more than my model 3 Tes, so I am willing to try anything to not get rid of it at this point.

But yeah, that's why I am afraid of taking it to Acura, but dude, I've tried everything and my mechanic too, and he's been doing this for 20+ years....but you're right, it could be something as simple as the suspension. I've never heard of this, but shoot, I'll give it a try...I bought the kit off eBay, and it made a hugee difference, but living in Florida, with the **** ton of pot holes, it may have thrown it off or broken something along the way....gonna check it out today, and see. Thanks again 馃

I bought Satan's old MDX so I've gotten a bit good at working on it, lol. It's also a 2005 so it's not worth it to me to actually take it to the dealership unless I absolutely have to. There are also very few true mechanics left at dealerships, most are an Acura tech at some level which typically means they're dependent on computers to tell them the problem. When it came to the suspension I took it in and paid to have the car checked out top to bottom and they said other than an oil leak it was fine. The codes kept coming ,and they were always misfire codes. When I noticed how inexpensive the suspension kits were, I decided to give it a shot. Don't forget there are several arms, braces, air rods and bearings on each side. The car was completely out of square/balance the front end was forced up and out so much so that they had 3 different people reset the alignment machine to make sure that they were really that far out.
 

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If you've actually replaced all the suspension it likely hasn't gone bad, but damn near everything on an MDX needs to be replaced around 100,000 miles. The codes being thrown constantly on the same cylinders to me suggests that it's definitely not actually misfiring. MDXs are expensive as hell yet most of their electronics always wide up being crap, ask anyone with their infamous electronic shocks.
Going through the system there are only certain things that should be able to cause a misfire. Too much oxygen, bad fuel, not enough oxygen, bad coil pack, an unidentified vibration, or a bad computer. My transmission went bad and I wasn't in a position to buy another vehicle so I replaced it and that sealed my fate of making it last as long as possible lol.
A vacuum leak may possible because it seems like it's every other cylinder. Possibly a bad computer. I don't know if a shop could test it but you could get one from a junkyard give it a shot and see if it codes come back. If they don't you can return the computer if you want and buy a new one. Given that it's happening at low speeds would suggest a vibration that the computer can't identify simply because like an unbalanced washing machine the vibration eases as speed picks up. The passenger side motor mount and the front motor mount are extremely easy to replace, any special tools can be rented from any auto parts store for a fully refundable deposit
 

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damn near everything on an MDX needs to be replaced around 100,000 miles. The codes being thrown constantly on the same cylinders to me suggests that it's definitely not actually misfiring. MDXs are expensive as hell yet most of their electronics always wide up being crap
Yikes! Talk about unlucky. My 2008 is at 175K miles and has zero misfires and electronic issues whatsoever outside some torn wires in the driver's door harness, which is a $20 part that is replaced in 15 minutes.
 

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Yikes! Talk about unlucky. My 2008 is at 175K miles and has zero misfires and electronic issues whatsoever outside some torn wires in the driver's door harness, which is a $20 part that is replaced in 15 minutes.
You're a lucky man Mr.Addicted, lol. My MDX is one year out of a multi-million vehicle recall from Acura due to the transmissions actually disintegrating. Acura has had a ton of recalls just go to their site and type in your vin number to see if your vehicle is involved. If you've never heard of the term rehousing your oil pump, YOU WILL. Acura uses very few actual gaskets and mostly sealants, you'll have to take apart the entire front of the engine to run a new line of sealant on the oil pump. The list goes on and on. Acuras are extremely expensive and if you can afford to purchase one new and replace it every 4 years I doubt you'll ever see a major problem, but once the warranty is up WATCH OUT because it's a gamble at best.
If I were in a position to I would probably go with a lower end BMW over a higher end Acura, simply because BMW has a very long and well earn record.
 

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You're a lucky man Mr.Addicted, lol. My MDX is one year out of a multi-million vehicle recall from Acura due to the transmissions actually disintegrating. Acura has had a ton of recalls just go to their site and type in your vin number to see if your vehicle is involved. If you've never heard of the term rehousing your oil pump, YOU WILL. Acura uses very few actual gaskets and mostly sealants, you'll have to take apart the entire front of the engine to run a new line of sealant on the oil pump. The list goes on and on. Acuras are extremely expensive and if you can afford to purchase one new and replace it every 4 years I doubt you'll ever see a major problem, but once the warranty is up WATCH OUT because it's a gamble at best.
If I were in a position to I would probably go with a lower end BMW over a higher end Acura, simply because BMW has a very long and well earn record.
BMW reliability is far worse than Acura.
I did an oil pump reseal and it was a straight forward and there nothing like you said take part the front engine.


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I would say we will have to agree to disagree on the BMW vs Acura but I spent several years in Germany. And as far as for rehousing the oil pump, I did mine myself as well. I replaced the timing belt, water pump, serpentine belt tensioner, serpentine belt, oil pump filters, the o-ring INSIDE the oil pan that is suppose to be replaced when you rehouse the oil pump, and resealed the oil pump itself. The only thing that didn't HAVE to come off to get to the oil pump was the water pump, I replaced that since I was that deep. You also have to drop the exhaust completely and remove the oil pan to get to the inner o-ring. There might be a bit of sarcasm in my original message but I assure you to do it properly the entire front end has to come apart.
 

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You're a lucky man Mr.Addicted, lol. My MDX is one year out of a multi-million vehicle recall from Acura due to the transmissions actually disintegrating. Acura has had a ton of recalls just go to their site and type in your vin number to see if your vehicle is involved.
Second generation MDX does not have transmission issues and any recalls associated with its replacement.

If you've never heard of the term rehousing your oil pump, YOU WILL.
You mean the oil pump resealing? Yeah, just did that myself about a month ago. I'd say it's pretty reasonable to a 175K mileage.

Acura uses very few actual gaskets and mostly sealants, you'll have to take apart the entire front of the engine to run a new line of sealant on the oil pump.
That's just nonsense. The oil pump is located on the right side of the engine, under the timing belt. You do not need to "take apart the entire front of the engine" to reseal it. Just take the oil pan off, timing belt off (that's why it's recommended to be done during the TB replacement) and take the oil pump off. It's actually not that difficult, just tedious and uncomfortable. But definitely DIYable (as I said, I did that myself for the first time about a month ago). The video will come out late in the fall.

The list goes on and on.
Do let us know the entire list, please.

Acuras are extremely expensive and if you can afford to purchase one new and replace it every 4 years I doubt you'll ever see a major problem, but once the warranty is up WATCH OUT because it's a gamble at best.
Basically I disagree on every point in this sentence. First of all, buying a new vehicle is not a good investment as it's a quickly depreciating asset. You can get a used one for much cheaper. For example, I got my 2008 back in 2011, so it was 3 years old. For half the price of the new one. I've had this car for 9 years now and it's still in great shape with no major issues. Of course, it's regularly maintained and any repairs done ASAP to avoid making it worse. However the repairs cost have not come even close to the difference between the used car I got (for half the price) and if I bought it new. Basically, buying a new car cannot be justified for me.

If I were in a position to I would probably go with a lower end BMW over a higher end Acura, simply because BMW has a very long and well earn record.
LOL, you, sir, made my day. Just for reference, last year I've replaced the valve cover gasket for my friend's BMW X5. I spent about 6 hours disassembling the entire top of the engine bay in order to get to that damn gasket and then another 6 hours assembling everything back. That BMW wasn't even at 100K miles and already leaking from under the valve cover gasket. BMW quoted a whopping $1400 for the job.
 

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I would agree that pretty much any vehicle actually made in Germany has a completely different quality, likely due to the European highway system (aka. the Autobahn). I listed everything that has to come off to do a complete oil pump rehousing, and I actually forgot to mention removing the harmonic balancer and the oil filter mount itself. I won't continue to argue my point all you need do is buy yourself a Chilton's manual. A COMPLETE rehousing includes replacing all the internal and external seals, screens, and gaskets of the entire oil system. You CAN do a partial job and choose to replace only what you want but that's not a complete reseal. So good luck with your Acura
 
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