[prepster]

Ive searched throughout the forum and didn't find an answer besides replacing the fuel pump which i did. My car has 68k miles on it and i dont have any type of warranty on it. Ive done all the maintaince i can do to bring it as close to top shape as possible...oil flush, transmission drain and refill, brake flush with new brakes etc...but my engine still has minor shakes and has small vibration on and off for the first three minutes during cold start ups. what could this be? faulty fuel injectors? or is this normal? I plan to do the techron injector cleaning once i get closer to my next oil change if it is the injectors.

[Blk07335i]

If it only happens at cold start up I wouldn't worry about it. Mine is a little rough as well until it settles at idle. I have 58K miles.

[wtfmateim65]

The infamous n54 idle shakes. Almost everyones got em. Troubleshooting options: spark plugs, coils, injectors!

Did u get the injector recall done already?

Some techron should help periodically.

It's usually the spark plugs though, if not people have a bad injector or two, otherwise it's the coil packs acting up. Don't depend on the dealer completely to diagnose because they will run you in circles, tell you it's normal, or tell you "unable to duplicate customer concern" or some amateur hour bs like usual

[wren57]

Change your spark plugs.

I think I recall reading where fuel injector additive you put in your gas tank is useless in our DI cars. Am I wrong?

[wtfmateim65]

Originally Posted by wren57

Change your spark plugs.

I think I recall reading where fuel injector additive you put in your gas tank is useless in our DI cars. Am I wrong?

You are right for cleaning the valves, since the fuel doenst wash over injectors in DI,but techron will still clean the injectors and cylinders walls since it's in the fuel

[JoosyJoos]

Could also be your motor mounts... And you're only noticing it on cold start where it revs it up above normal idle range at standstill.

[Robert H]

I'm curious whether you had the HPFP related recall work done on your car.

I took my '07 w/ 57k in for the recall about a month ago due to long crank and malfunction light/reduced power issue. The dealer replaced HPFP, a couple of injectors and reprogrammed the car. It came back from the dealer running extremely rough after every cold start...stutters/misfires for the first few minutes and then runs normal. It never did this before the recall work was done.

I took the car back to dealer Tuesday and they called to tell me the cold start is due to carbon buildup and has nothing to do with the recall work. I guess that could be the case but I'm a little skeptical. The dealer is calling BMWNA to see if they will cover the repair cost.

If you search "rough cold idle" there is at least one other person who experienced the same after recall repair. Anybody else?

[genuinekid]

Originally Posted by Robert H

I'm curious whether you had the HPFP related recall work done on your car.

I took my '07 w/ 57k in for the recall about a month ago due to long crank and malfunction light/reduced power issue. The dealer replaced HPFP, a couple of injectors and reprogrammed the car. It came back from the dealer running extremely rough after every cold start...stutters/misfires for the first few minutes and then runs normal. It never did this before the recall work was done.

I took the car back to dealer Tuesday and they called to tell me the cold start is due to carbon buildup and has nothing to do with the recall work. I guess that could be the case but I'm a little skeptical. The dealer is calling BMWNA to see if they will cover the repair cost.

If you search "rough cold idle" there is at least one other person who experienced the same after recall repair. Anybody else?

i am in a similar situation. Mines a 08 w/ 38k miles. Due to the rough idle, i so far had 6 spark plugs, injectors, changed, the hpfp changed, updated software all under warranty. But even after that i had a simi rough idle at stops. And now, they are cleaning my valves since due to carbon buildup. They are decarbonizing? or something.

[prepster]

Originally Posted by JoosyJoos

Could also be your motor mounts... And you're only noticing it on cold start where it revs it up above normal idle range at standstill.

yeah it only happens when the engine is cold at start up around 700 rpm. Ive read the repair manuall and can someone confirm if when replacing the fuel injectors, you have to calibrate them on the computer with the bmw software? Meaning only the dealerships or independant shops can do this? I plan to replace the spark plugs within the next oil change. I will also BG engine decarbinizer to clean the valves, and also run chevron techron as well to clean the injectors. is there anything else i can try?