EvolutionVIII

my 545i recently has been acting up. Sometimes when i come to a complete stop and take off, the car would jerk just a little when taking off, almost like a hesitation, like a little stumble in the gas pedal and when it smooths out it jerks and takes off smoothly after that. Now within the past few days the cars idle stumbles a little bit and when i go to take off the car stumbles alot and dies and cuts out. i put the car in neutral and try and start it and it would just crank. then i put it into park it cranks a little longer than normal and starts up but with a hesitation. I currently have no CEL on at the momment. But every now and then i will throw a code for P0444 evap code, but that code has been on and off since i first bought the car and it never did it before. the car has over 100K on it and i purchased some new spark plugs and air filter and cabin filter, but my feeling tells me its a fuel problem. any information anyone has will be appreciated. thanks.

healthservices

I'd start by looking for vacuum leaks, even a loose oil fill cap could do this. If those are OK, try cleaning you MAF sensor and throttle body.

Have you done anything recently to the car?

EvolutionVIII

Not really engine wise. I was planning on doing the tuneup but i want to fix this problem. Gonna check for all those an clean my MAF and see what happens.

pauliehcfr

Sounds like a fuel pump going bad. Check the fuel pressure at the injector rail

healthservices

Actually if it was fuel pump related the car would nosed over at rpm, and under load, rather than at idle.

pauliehcfr

I've seen them act like this so I was just throwing some leads out there. They don't have an idle valve so thats out. Only cause for this issue without a CEL would be fuel related.....

EvolutionVIII

That's what I'm thinking. It has to be fuel related.

healthservices

Does it ever lose power or want to quit at under load?

EvolutionVIII

No when I first go to take off under a light throttle it will stumble and stall. But if I rev it up hard and then go its good all after that. Steady 40-50 mph or any speed has no problems. Only when I first take off.

EvolutionVIII

This stumble has been happening for maybe 3 weeks but it never stalled just jerked a little when taking off i thiught it was the trans. But into maybe the 2nd week it stalled once and just on Saturday is when it stalled like 5 times within 5 minutes of driving. Almost every time I stopped the idle would stumble and when I take off it would stall as if it wasn't getting gas. I haven't driven the car since then or checked it out since I don't really use the car on weekdays.