[Slidewayz]

I'm kind of stumped on this one...hope someone can help !

It starts up fine (no long crank) but then the idle drops intermittently and when I'm driving, especially at low RPMs, the car 'stutters' / loses power. After the car is warmed up and at higher RPMs it is not so noticeable.

This started after I filled up my car but the overflow shutoff on the pump didn't work. I was on the other side of the car checking the tires so gasoline spewed out for about 5 seconds...correlation is not causation, but still...

Any thoughts on what the problem might be or how to diagnose ?

Thanks !!!

[Turb0Surge]

From the sound of it looks like A. You either have a bad fuel pump. B. Spark plugs. Or C. Coil packs.

Start with the spark plugs, they're the least expensive.

[Slidewayz]

Originally Posted by Turb0Surge

From the sound of it looks like A. You either have a bad fuel pump. B. Spark plugs. Or C. Coil packs.

Start with the spark plugs, they're the least expensive.

Thanks. The spark plugs have <5k miles on them, so that's probably not it. It's not throwing any codes, so can that be the coil packs or fuel pump.

What is the best way to figure out which it is so I don't waste $$$ ???

thanks !!!

[Turb0Surge]

Did you use OEM bosch spark plugs?

You can test the coil packs by turning on the engine and taking them off one by one. If the engine starts sputtering even worse then that pack is good. If you take one out and nothing changes then that coil pack is bad.

Fuel pump would be hard to test, because if the fuel pump is completely shot, the car won't start. But it could be starting to go out, in which case the fuel would not be getting to the injectors as it should be and that could be where the sputtering is coming from.

[happy4nk8er]

Might have something to do with fuel in the emission system loop. The system knows when we have not put the gas cap back on tight enough, so maybe fluid has gotten in the the emission vacuum system. Any codes?

[Slidewayz]

Originally Posted by happy4nk8er

Might have something to do with fuel in the emission system loop. The system knows when we have not put the gas cap back on tight enough, so maybe fluid has gotten in the the emission vacuum system. Any codes?

No codes.

[hemi to e90]

u have downipipes? when did you put them in?

[Slidewayz]

Have DPs, DCI, Helix IC, and proCede 2.5.

Everything has been in the car for 20k+ miles and no new map or firmware has been flashed in 1+ months.

[Dr_Dirt]

Take out the procede and test again, maybe you got a loose wire in the harness.

[RaddM4]

I just had the same problem. My plugs, coils, and high pressure fuel pump are brand new. Mine was the low pressure fuel pump.

[Slidewayz]

Originally Posted by raddinteractive

I just had the same problem. My plugs, coils, and high pressure fuel pump are brand new. Mine was the low pressure fuel pump.

Did you get any codes ?

[themyst]

Dumb question, are you using E85?

[Slidewayz]

Originally Posted by themyst

Dumb question, are you using E85?

No.

[hemi to e90]

Originally Posted by themyst

Dumb question, are you using E85?

now I'm curious why u asked?

[Joshboody]

evap charcoal thingy got fuel in it.

[themyst]

When you run E85, some cars will have an inconsistent idle which goes away after warming up or driving WOT.

His issue sounded like he was trying E85. Since that's not the case, it's plugs, coils, or intake valve gunking. If you have cold start misfires, injectors.

[zztwinturbozz]

Injectors? Maybe clogged up intake valves? Try dumping a bottle of seafoam in the tank and floor it around for a while.

[MilehighM3]

If it happens after refueling, it's probably your fuel tank valve valve/purge valve sticking open. Allowing fuel and or fuel vapor into the intake when it shouldn't. Also explains why the pump didn't shut off at the gas station, no back pressure build up in the filler neck as a result.

[happy4nk8er]

What he said sounds pretty damn convincing. That might have allowed fuel to get into your carbon emission can( as someone else mentioned) or cans I think there might be 2.

[Slidewayz]

Originally Posted by Joshboody

evap charcoal thingy got fuel in it.

That was it !

Thanks !

[mannytabloid]

Hey, sorry to revive a dead thread. The exact same thing happened to me. Does anyone have a part # or more details on what I need fixing?

[TenshiWingusu]

Originally Posted by mannytabloid

Hey, sorry to revive a dead thread. The exact same thing happened to me. Does anyone have a part # or more details on what I need fixing?

16137163596 Probably the part number

http://realoem.com/bmw/ to find part numbers

then

http://getbmwparts.com/ to buy them