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kge42 11-02-2012 10:46 AM

Missing after waterpump. radiator change and sparkplug
Hi new member here, I have a 1998 740iI that I replaced the radiator and water pump. In a test drive everything was great, the next time I drove it, it started running rough. Changed spark plugs (Bosh) it was better, but was missing at idle and seems to be getting worse. Seems OK until it warms up. Any ideas?

seamus2154 11-09-2012 07:48 PM

I would check all of your air intake hoses and clamps. Make sure you didn't crack a pipe. Then move onto the MAF and o2 sensors. Any codes?

BigBoy740il 11-18-2012 02:54 PM

You might want to retrace your steps. Is the Check engine light on? Did you have the codes read? You said you changed your spark plugs. Was any of the old plugs covered in oil? Did you replace the spark plug boots? Did you remember to replace the coil pack grounds? When you replaced the water pump and radiator, did you ensure the intake tubes were properly connected (vacuum leaks).

dUMpEdE39 11-26-2012 11:41 AM

+1 on checking the coils

PETER NEWMAN 12-01-2012 01:57 AM

My suspicion is that your head gasket is leaking because if you also filled your cooling system with fresh anti freeze the new anti freeze has found a weak spot in one or both head gaskets.

bluebee 12-02-2012 11:29 AM


Originally Posted by kge42 (Post 7172000)
missing at idle and seems to be getting worse.

If it's misfiring that badly, there should be codes.
- Cheapest CAN OBDII scanner on the net that reads DTCs, pending codes, & clears codes

Once you have the codes, go here:
- How to diagnose a BMW engine misfire (1)

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