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Discussion Starter · #1 ·
Hey guys so I’ve got a 2003 330i and I’m having trouble diagnosing what’s wrong with the car. Out of nowhere the car shakes pretty good at idle and has a large loss of power when driving. It threw codes for cylinder 3, 4, and 5 misfire and fuel cut off. I replaced the fuel pump knowing how troublesome they can be yet the car still does the same thing. It has all the symptoms of a bad tps but to my understanding the tps is built into the throttle body and I’m not sure if the pedal sensors are something that’d create this issue. Any advice or info is greatly appreciated.
 

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2001 325i MT, 2001325i ZF auto,1999 328is auto
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What's causing the fuel cutoff? Are the plugs firing or is the something wrong with them?
Pull the plugs and look for something that will prevent them from firing. Post back your findings.
 

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Discussion Starter · #4 ·
What's causing the fuel cutoff? Are the plugs firing or is the something wrong with them?
Pull the plugs and look for something that will prevent them from firing. Post back your findings.
Plugs are newer, misfire code jumps between all cylinders randomly. It’s not consistent to any cylinder/s. It doesn’t appear to be a coil pack or spark plug issue.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Something you need to know:

Fuel cutoff is NOT a bad fuel pump.

Starting in 1/1995 if any cylinder was misfiring long enough, it became mandatory for the engine computer to turn the fuel injector off. So as to not pollute the air.
Like that smoking black plate 63 Chevy Bel Aire that's running on 6 1/2 of it's 8 cylinders running down the Ventura Freeway.
It's also why Mercedes had to turn it's back on it's venerable Bosch CiS E system. No way to turn off a dirty cylinder.

So you have a misfiring cylinder(s) that happened enough to shut off the injectors to stop flooding the exhaust system (outside air) with raw unburnt fuel.

Most common culprit is coils and/or plugs.
 

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Discussion Starter · #8 ·
Something you need to know:

Fuel cutoff is NOT a bad fuel pump.

Starting in 1/1995 if any cylinder was misfiring long enough, it became mandatory for the engine computer to turn the fuel injector off. So as to not pollute the air.
Like that smoking black plate 63 Chevy Bel Aire that's running on 6 1/2 of it's 8 cylinders running down the Ventura Freeway.
It's also why Mercedes had to turn it's back on it's venerable Bosch CiS E system. No way to turn off a dirty cylinder.

So you have a misfiring cylinder(s) that happened enough to shut off the injectors to stop flooding the exhaust system (outside air) with raw unburnt fuel.

Most common culprit is coils and/or plugs.
I pulled the cylinder 3,4, and 5 plugs and they are all fairly new and in good shape. I marked and swapped coil packs around and no difference. It seems to be an issue covering all cylinders but I suppose you could be right.
 
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