e39 523i misfiring, wont accellerate properly

DannyW

DannyW

DannyW

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hi guys my 523i has been fine for 3000 miles since i bought it but this week when pulling up the the lights the revs have dropped so low its nearly stalled then it picks its self up and has been fine. Tonight i went out and at like 30 mph in 4th gear when i try and accellerate it just goes very juddery and shaky and doesn't get faster. Pulled over turned it off and back on agen and it seems fine but the revs still drop too low when pulling up at the lights.

Could it need new spark plugs? Dont know when they were last changed

I know its had a recent cam or crank shaft sensor i can't remember which

Any other suggestions?
 
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tradational cause of misfire is either Coil Packs or Spark plugs.

Let us know how much the bill is to get it fixed :)
 
Misfire can be caused by:

a) Failed Camshaft position sensors
b) Failed Crankshaft position sensors
c) Sticking Idle Control Valve
d) Heavily clogged CCV
e) Spark plug issues
f) Coil pack issues

The obvious thing to do would be to check the fault codes.
 
ideally you'r going to have to find somebody who can pull the codes, then swap the coil packs round.

If the fault stays on the same bank (assume the code will tell you on what bank the misfire occurs ?) then the next possible culprit is the spark plugs. Get them changed and see where that gets you. If the fault follows the coil packs then obviously they'll need replacing.

If its not those, then you'll need to check the other stuff fox mentioned. Best of luck !
 
This happened on my 320i when the mechanics forgot to plug the camshaft sensors back up. It will show up on diagnostics if it is that
 
[TW]Fox;16125156 said:
Misfire can be caused by:

a) Failed Camshaft position sensors
b) Failed Crankshaft position sensors
c) Sticking Idle Control Valve
d) Heavily clogged CCV
e) Spark plug issues
f) Coil pack issues

The obvious thing to do would be to check the fault codes.
Click to expand...

Pretty much that, the last 2 are the most common, I'd start there, particularly if there are no faults logged.
 
The spark plugs should have been changed when the car last had an Inspection II, assuming it has followed BMW servicing schedules (something tells me that it hasn't).
 
ok thanks very much for that

it could be a blocked fuel line or filter because it was run out of petrol a few days ago
 
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