Randomly enters into limp (?) mode- rough idle

[upallnight]

A misfire in today modern computer controlled engine is not the same as a misfire in the old carburetted engine of days gone by. A misfire in today engine means the computer has detected that one cylinder or multiple cylinders are not providing as much power when it fires as compared with the other cylinders. A lean condition could account for a misfire as well as an unhealthy engine with low compression in one or more cylinders. So don't go by the old way of thinking that a misfire is only related to spark plug and coil.

[andrewwynn]

That's very accurate. The crankshaft position sensor measures how far the engine turn each time a cylinder fires and if it's delayed by milliseconds it knows that that cylinder didn't do its job correctly

[mcfee03]

Limp mode is beginning to happen more often

I don't have my odb with me, so no codes.

Turning the engine off for about 1 seconds gets rid of it.

Also, it seems to be (maybe) chewing through a lot of fuel.

Just so I understand- my first recommended step it to replace the plugs? My local store sells Bosche- is it worth delaying to get NGK?

Is there anything to look for on the plugs or coils- I remember once hearing about a mayonnaise like substance being an indicator of something?

Then coils? Then the crankshaft position sensor?

[andrewwynn]

It sounds exactly like wife's car and was just plugs.

I cleaned and gapped her plugs and it ran much better until I got plugs. I think I may have used Bosch Platinum 4 in her car.




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[mcfee03]

Just replaced all the spark plugs (with Bosche)- and sadly the car just entered into limp mode after about 10 minutes of drivung

Odb codes are now:
C3113- Chassis (haven't seen this before, only popped up once...)
P0001- power train
P0155- o2 head sensor
P0171- too lean (bank 1)
p1349- misfire cylinder 4
P1351- misfire cylinder 5
P1353- misfire cyclinder 6
P0300 random misfire
p1346 misfire during start cylinder 6

Is torque/tension on spark plugs/coils important? I definetly had difficulty getting the back plugs in tight.

What is next to do?

[upallnight]

Originally Posted by upallnight

P1349 BMW - Misfire Cylinder 4 With Fuel Cut-Off

P1351 BMW - Misfire Cylinder 5 With Fuel Cut-Off

P1352 BMW - Misfire During Start Cylinder 6

Base on what you wrote and the codes you posted, you have a misfire(s) with injector cutoff. Restarting the engine just reset the misfire counter back to 0 and the injector(s) that was turned off by the computer is now back on. Could be a bad plug(s) or a bad coil(s). It would be cheaper right now to just replace the plugs if they haven't been done recently.

Other things to look at because you have 3 cylinders that are misfiring is for an Intake vacuum leak or a Faulty Camshaft Position Sensor.

Did you look for a vacuum leak? You have a P0171 lean code which will be a vacuum leak. Check the rubber boot from the MAF to the throttle body, in particular, the rubber extension to the Idle Air Control valve. That is a known leaker.

[andrewwynn]

I had that exact leak. I didn't know about it until my disa failed. Terrible idle. I looked for a leak and my finger went right into the hose


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[upallnight]

Originally Posted by mcfee03

Limp mode is beginning to happen more often

I don't have my odb with me, so no codes.

Turning the engine off for about 1 seconds gets rid of it.

Also, it seems to be (maybe) chewing through a lot of fuel.

Just so I understand- my first recommended step it to replace the plugs? My local store sells Bosche- is it worth delaying to get NGK?

Is there anything to look for on the plugs or coils- I remember once hearing about a mayonnaise like substance being an indicator of something?

Then coils? Then the crankshaft position sensor?

If you have a scanner that can show real-time activities, you can look at the long term and short term fuel trim. If you have positive fuel trim that means the computer is adding fuel to the mixture. This could be because the engine sees a Lean condition so it is trying to compensate for a lean condition. I would find out what the problem is before driving the X or else all that excessive fuel is going to ruin the catalytic converter, assuming in your neck of the wood you have catalytic converters on your cars.