Misfire at idle, can't solve.

[Simonmiller]

Hey guys, having an issue with cylinder 3 misfire and sometimes more. I'll be at a light sitting at idle and if I don't rev-up the car to 1.5kish rpms, it will drop to 500-800rpms and in a couple minutes i'll have at tremendous loss of power and engine shake (definitely a misfire) so I pull over and restart the car and it's fine until im at idle and it happens again. The codes that I've been constantly getting over the last month have been P0303 (cylinder 3 misfire) p1188 p1189 p0170 p0173 which all have to do with fuel running lean. Every once in a while it'll read a couple cylinders but 95% of the time it's cylinder 3. I've replaced sparks and swapped around coils and reset code to see if it followed but it was still cylinder 3. Then proceeded to swap Valve Cover Gasket just because it probably needed it anyways. Also swapped MAF and replaced O2's but no solution. It seems to be some sort of fuel issue. Inspected and replaced all vacuum leaks I could see. I have a feeling it could be something with the CCV or possibly the injectors. I don't want to just throw money at potential problems. Just a college student trying to save the money I got, if anyone has any idea or past experience with this issue any help would be amazing. I don't want to have to bring it to a shop just to get charged out the a** when I can DIY with the help of this amazing forum. Thank you.

[jclausen]

If you go to a good shop and they dx it correctly then your going to save a bunch of time and energy. Most shops have good people working there, that's what they do. There not a bunch of assholes. Have some respect for the technicians who have huge amounts of training and tools. It's always the same thing people want there car fix but don't want to pay for the services rendered. There just like you they go to work and work on cars for a living, making house payments, having a family etc. show some respect

[Simonmiller]

If you go to a good shop and they dx it correctly then your going to save a bunch of time and energy. Most shops have good people working there, that's what they do. There not a bunch of assholes. Have some respect for the technicians who have huge amounts of training and tools. It's always the same thing people want there car fix but don't want to pay for the services rendered. There just like you they go to work and work on cars for a living, making house payments, having a family etc. show some respect

Seems like a personal problem buddy, said I’d rather save money and DIY because shops rates are expensive. Not once did I “disrespect” them, get out of this thread if you’re not gonna be helpful

[BladeRunner919]

What engine are we talking about here?

[Vintage42]

Seems like a personal problem buddy, said I’d rather save money and DIY because shops rates are expensive. Not once did I “disrespect” them, get out of this thread if you’re not gonna be helpful

The auto shops read codes for free. And, it would be helpful and improve responses if you had added your year and engine to your My Cars.
Mr. Simonmiller, your language is unusual for this forum, and I am out of your thread.

[Simonmiller]

The auto shops read codes for free. And, it would be helpful and improve responses if you had added your year and engine to your My Cars.
Mr. Simonmiller, your language is unusual for this forum, and I am out of your thread.

Understood, not intended to be. Just don’t know why he’s acting like I talked down on mechanics when all I was stating was that the prices are too high. The car is a 00’ 2.3 or (2.5) M52TU

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What engine are we talking about here?

2.5 M52TU

[me77]

I found something that says that the little rubber boot for the idle control valve often has a leak and causes issues like that:
OBD II Codes- (P0170/P0173/P1188/P1189)

What is your idle speed cold and warm?

[chuter]

Simonmiller , I think jclausen is correct. You probably have spent more money DIY than a proper dx from a dealer. JMO and I'm out of here too.

[Simonmiller]

I found something that says that the little rubber boot for the idle control valve often has a leak and causes issues like that:
OBD II Codes- (P0170/P0173/P1188/P1189)

What is your idle speed cold and warm?

Already replaced lower intake boot forgot to mention that. It stays around 1k whether cold/warm then drops when it’s about to misfire or cut off cylinder 3.
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Simonmiller , I think jclausen is correct. You probably have spent more money DIY than a proper dx from a dealer. JMO and I'm out of here too.

Most everything I replaced needed to be replaced anyways, but understood, thanks anyways.

[solimans]

Hey guys, having an issue with cylinder 3 misfire and sometimes more. I'll be at a light sitting at idle and if I don't rev-up the car to 1.5kish rpms, it will drop to 500-800rpms and in a couple minutes i'll have at tremendous loss of power and engine shake (definitely a misfire) so I pull over and restart the car and it's fine until im at idle and it happens again. The codes that I've been constantly getting over the last month have been P0303 (cylinder 3 misfire) p1188 p1189 p0170 p0173 which all have to do with fuel running lean. Every once in a while it'll read a couple cylinders but 95% of the time it's cylinder 3. I've replaced sparks and swapped around coils and reset code to see if it followed but it was still cylinder 3. Then proceeded to swap Valve Cover Gasket just because it probably needed it anyways. Also swapped MAF and replaced O2's but no solution. It seems to be some sort of fuel issue. Inspected and replaced all vacuum leaks I could see. I have a feeling it could be something with the CCV or possibly the injectors. I don't want to just throw money at potential problems. Just a college student trying to save the money I got, if anyone has any idea or past experience with this issue any help would be amazing. I don't want to have to bring it to a shop just to get charged out the a** when I can DIY with the help of this amazing forum. Thank you.

from what little i know...try a fuel pressure test. or swap the third and forth injectors and see if the misfire moves? bad injector?

sounds like a vacuum leak...from what little i know

[Simonmiller]

from what little i know...try a fuel pressure test. or swap the third and forth injectors and see if the misfire moves? bad injector?

sounds like a vacuum leak...from what little i know

I’ll try the injectors, also thinking its a vacuum leak but inspected all of them besides CCV. Thanks for the reply!

[solimans]

I’ll try the injectors, also thinking its a vacuum leak but inspected all of them besides CCV. Thanks for the reply!

yes sir. maybe a smoke test for the vacuum leaks...that could get it

[z3forlife]

Smoke test will find your vacuum leaks if any

[Simonmiller]

yes sir. maybe a smoke test for the vacuum leaks...that could get it

Probably will end up doing that this week or so. Hopefully I find the problem, thanks!

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Smoke test will find your vacuum leaks if any

^^^ thanks!

[328 Power 04]

Smoke test with a proper tool that can pressurize the intake tract (this tool works well https://www.ebay.com/itm/264134468462 ) and fuel pressure test at idle and revving.

[Potes]

Nothing simonmiller said is out of hand, he’s an enthusiast who wants to do the work himself like all of us.. dunno why everyones being an asshat rather than helping ..


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[Potes]

if the solution to every question posted on the forums is “go to the stealer” then the forums wouldnt exist at all, lotta people being irrational to a kind respectful guy with a misfire


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[jclausen]

If and when he gets tired of not being able to figure out the misfire, then he might think of looking for a good independent BMW shop to diagnosis the problem, not the dealer ship. Then you might strike up a relationship with that shop who can help you out with future needs. It's not about people working on there car, it's about getting tired of not being able to solve the problem and seeking help and stopping them from throwing parts at the car. Everybody eventually needs help with something they don't know about and that's ok.

[BimmerBreaker]

Have you tried cleaning the ICV?

[me77]

Me and the thread opener are the only ones in this thread that have suffered from expensive "professionals" it seems. Often when I had a car in the shop for repair, they didn't really fix the original issue, broke something else in the process and told me "it came in like that". Sure as hell it didn't. Since then I fix everything myself, which has turned out to be much cheaper, better and less stressful.

ICVs on these cars can gum up? From what I've seen, there isn't really a way for it to get stuck. If you do take it out, do not move it manually with a screwdriver or something because that will break it according to BMW.

[Simonmiller]

if the solution to every question posted on the forums is “go to the stealer” then the forums wouldnt exist at all, lotta people being irrational to a kind respectful guy with a misfire


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Spot on, appreciate it!

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Have you tried cleaning the ICV?

Have not tried that, haven’t heard of much people saying they had problems with it but I’ll give that a check. I’m thinking it’s the CCV and could have failed internally & a smoke test couldn’t find that so I’m going to replace it and hopefully it will fix!

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Me and the thread opener are the only ones in this thread that have suffered from expensive "professionals" it seems. Often when I had a car in the shop for repair, they didn't really fix the original issue, broke something else in the process and told me "it came in like that". Sure as hell it didn't. Since then I fix everything myself, which has turned out to be much cheaper, better and less stressful.

ICVs on these cars can gum up? From what I've seen, there isn't really a way for it to get stuck. If you do take it out, do not move it manually with a screwdriver or something because that will break it according to BMW.

Also the fear I have bringing it somewhere since these cars are about 20 years old, stuff is more fragile.

[Randy Forbes]

While I have seen ICVs that were sticky (simple to clean out w/carb cleaner) they're not so selective to cause only one cylinder__#3__to misfire.

Likewise the CCV, which I doubt you have any problems with.

Do what someone else suggested and swap the #3 injector with another cylinder and see if the problem follows it. Since you already swapped plugs and coils, my money is on the injector (plug condition/color would've been an indicator).

If you're still getting misfires on #3, then do leakdown & compression tests, as your problems may be a gasket breach, broken ring(s) or burnt/bent valve(s).

If the problem DOES follow the injector, get them ALL cleaned/calibrated by a reputable company (I use Injector Rx).

[Randy Forbes]

A more in depth look at solving a misfire condition, and in this case, the solution to finding a fault leading to it in a similarly engine'd vehicle (X5 3.0).

The real takeaway here, is that it is not economical to just throw parts at a problem, hoping that you get lucky and eventually find the one (or more) at fault. They do however, promote the practice of moving parts from one cylinder to another, in an effort to isolate the problem, but that even that is not a guarantee of success. Good luck, and I hope you get it figured out, but replacing the CCV is unlikely to fix a misfire on cylinder #3.

https://www.techshopmag.com/maximizi...19&bid=2374566

[Simonmiller]

A more in depth look at solving a misfire condition, and in this case, the solution to finding a fault leading to it in a similarly engine'd vehicle (X5 3.0).

The real takeaway here, is that it is not economical to just throw parts at a problem, hoping that you get lucky and eventually find the one (or more) at fault. They do however, promote the practice of moving parts from one cylinder to another, in an effort to isolate the problem, but that even that is not a guarantee of success. Good luck, and I hope you get it figured out, but replacing the CCV is unlikely to fix a misfire on cylinder #3.

https://www.techshopmag.com/maximizi...19&bid=2374566

I’ll check. Just swapped cylinder 3 injector with a different one. Reset code and rode around for a bit and it was still cylinder 3... don’t know what step to take next.

[Simonmiller]

I’ll check. Just swapped cylinder 3 injector with a different one. Reset code and rode around for a bit and it was still cylinder 3... don’t know what step to take next.

I’ve had the car hooked up to a reader and at idle, one of the O2 sensors wasn’t recieving the right voltage. When spraying carb cleaner where you put your oil in, it received proper voltage and the engine rev’d up. I really feel like it’s a CCV leak/internal failure & they seems to have problems somewhat often on these cars. Any advice on next steps to take would be great.