Hi everyone,

I am currently having a maddening issue with my 1998 420 Si, 16 valve T series 2.0 liter.

When I start it it's all fine but after driving for roughly 4-5 minutes, when it properly warms up, the ignition starts cutting for a millisecond. The idling is completely fine but it does this whenever I rev it. There is no specific RPM range for it to do it, it does this whenever I push the throttle.

My current suspicion is the crankshaft sensor as the coil was changed and the IAC was also changed and the problem pursues.

I would greatly appreciate all the feedback.

Thank you kindly.

I've only once had a crankshaft sensor fail (on my 1995 R8). There was nothing intermittent, it just died - the car was running fine, switched it off, went to restart and nothing.

I have had a similar issue with the car literally cutting out for a fraction of a second. It got much worse very quickly, but would then run fine the next time it started up. After a lot of trouble shooting a replacement ECU eventually solved the problem.

I think the best place to start would be with diagnostics. I believe these later cars are OBDII?? If you can pick up a code reader it might point you in the right direction. Hopefully somebody more familiar with the later models can be of more help.