[triggz]

Ok so I'm experiencing some weird issue recently.

As soon as I park my car and let it cool down, I hear this very subtle "pop" from the exhaust and then the rpms increase from 550rpm to 700-750rpm and they stay there. While they stay there I will hear the "pop" sound every 15-30 seconds. It happens everytime I put my car in park.

I'm not throwing any codes and I'm boosting with zero issues.

What could this be? Vacuum lines? Injectors?

I have new plugs btw. Bad plugs?

Should I be worried?

[triggz]

anyone?

[SlowerThanU]

Does it happen when warm? Unfortunately you need a pretty bad misfire to throw a code...trust me...I know.

If I were you I would check your plugs again. One of them should be different than the others and it should be easy to tell since they are new.

I am having the same problem and one cylinder keeps fouling out plugs...one of my new plugs was coated with carbon after two weeks.

Assuming you find a fouled plug, put in a new plug and swap a coil from another cylinder and see if the other plug fouls. If it does you found a bad coil. If the same cylinder fouls again, swap the injector.

[BrianMN]

You can definitely get WOT misfires without throwing codes; and I get them about after about 5k on the plugs. New plugs always solves it.

Those hiccups at idle are sometimes unexplainable. If it's significant at cold start, it is likely an injector.

[Jeff@TopGearSolutions]

I believe that is your injectors, possibly leaking or on their way out. However, this car doesnt have the smoothest idle to begin with.

[triggz]

Thanks guys!

It never did it before so I'm assuming it's either the plugs or injectors.

I was leaning towards injectors as well Jeff.

I highly doubt OEM plugs would do something like this. Also, I remember it happened once or twice before the plug swap.

Jeff, how will I know when it's time to change the injectors?

[E90SoFlo]

Originally Posted by triggz

Thanks guys!

It never did it before so I'm assuming it's either the plugs or injectors.

I was leaning towards injectors as well Jeff.

I highly doubt OEM plugs would do something like this. Also, I remember it happened once or twice before the plug swap.

Jeff, how will I know when it's time to change the injectors?

When plugs and coil packs don't fix it, its time to change injectors.

[Jeff@TopGearSolutions]

Originally Posted by triggz

Thanks guys!

It never did it before so I'm assuming it's either the plugs or injectors.

I was leaning towards injectors as well Jeff.

I highly doubt OEM plugs would do something like this. Also, I remember it happened once or twice before the plug swap.

Jeff, how will I know when it's time to change the injectors?

Originally Posted by E90SoFlo

When plugs and coil packs don't fix it, its time to change injectors.

Or when you have fuel related hardware codes

[triggz]

Update:

Brought the car to BMW and they said they could not find any codes or anything that can give them permission to do warranty work.

If it was the coils or injectors, wouldn't they be able to see that through the diagnostic?

Therefore, is it possible that these are just bad spark plugs? The issue literally started happening as soon as I changed the plugs.

[BMWsky]

Try inspecting each plug for irregularities, one of them might have been dropped or damaged causing the gap to be off. While inspecting them, see if there is any moisture on the threads as that would be a good indication of an injector going bad.

Honestly, I used to have the same issue only to have it just go away on its own. Very strange.

[bryce]

do you happen to be running a tune with auto code clearing? that could be one issue, if it's automatically erasing any codes that could be showing up.

the other possibility is that your injectors are beginning to fail. this is teh case a lot of times with stumbling rpm's at idle. the injectors flow well during driving and WOT pulls, but for some reason at idle, they cause minor issues. i'd keep an eye on the part throttle and WOT performance. if it is injectors, eventually those types of driving will be effected, too