325i stuttering

[M20b25]

Hi... Sorry about that...
My car seems to have a stutter between 1500- 3000rpm, changed my AFM//plug wires/plugs. I had the rotor/cap/ecu inspected and they appear perfect.
Could the injectors cause this ?
It's regardless of what gear i'm in...from 1st - 5th..

[silversleeper]

vacuum leak? i would definitely check the intake bellow (the elbow connecting the throttle body to the AFM.

[M20b25]

just checked the bellow, no cracks.
there 4 guys in our club with the same problem!

[HST]

TPS or crank positioning sensor maybe?

[Garageaholic]

bad O2 sensor

[King Luis]

let it idle for a bit and see if the check engine light comes on.
check you icv and what i noticed was a good tip was to put some oil around each injector to provide a better seal and see if the issue stops. i had stuttering occur a few weeks back. i did that and now its a lot better.
bad gas maybe?? did you all get it from the same gas station?

[n3nyongmini]

let it idle for a bit and see if the check engine light comes on.
check you icv and what i noticed was a good tip was to put some oil around each injector to provide a better seal and see if the issue stops. i had stuttering occur a few weeks back. i did that and now its a lot better.
bad gas maybe?? did you all get it from the same gas station?

You can quickly test the injector seal w/o removal:

while idling, spray a LITTLE carb cleaner/WD-40/aerosol of your choice at/near the seal. If you notice a change in idle, you have a leak. Which may be causing your stutter. Use only a LITTLE aersol as too much ain't so good for motor, cat etc....

HTH

Derek

[delatlanta1281]

just checked the bellow, no cracks.
there 4 guys in our club with the same problem!

I see a group buy in your future!

[M20b25]

Just got back from the BMW Technician, did some testing.. My Idle is almost spot, round 750+ rpm, the CO's are perfect as well. We kept the car at a constant rev at 3000rpm and noticed that there is way more O2 than Fuel in the mixture.. Anyone know what the hell this means ?

[Scott314]

Just got back from the BMW Technician, did some testing.. My Idle is almost spot, round 750+ rpm, the CO's are perfect as well. We kept the car at a constant rev at 3000rpm and noticed that there is way more O2 than Fuel in the mixture.. Anyone know what the hell this means ?

I'm gonna take a wild guess and say that there was 14.7 times as much air as there was fuel.

[Adrian_Visser]

lol, lol lol

but seriously if it is lean above the normal ideal mixture of 14 parts O2 to one part fuel like maybe 18 or 20 to one then couldnt it be a problem with the O2 sensor? i mean your not at WOT so the ecu is using the O2 sensor input

if it was lean than wouldnt you notice higher engine temps?

[silversleeper]

nothing a MarkD chip can't fix! ;)

[M42Technik]

Check your ICV. See if it whirrs when the car is ready to fire up, but not on position.

Hold the ICV and if it doesn't seem like its "whirring", then your ICV is bad, might need replacement. I replaced mine, and it did wonders.

[ed chitwood]

get a fuel pressure gauge make sure your pumps, and regulator are working right.