Surging at idle

1988 325i, convertable, tuned up ignition, cap etc. , took it to deq, did not pass, took it to a shop , note car was running great better than ever. Wife picked up car from adjustment. died 2 blocks away. something clicking when motor not running, relay? Got it started took it home. Checked all hoses, vacuum related. changed throttle switch sensor, idle valve, car starts ok , but surges now at idle . took to shop , code reader said idle control valve? installed new and old one, still surging, Mechanic pulled fuel line of of rail, no fuel pressure, changed fuel pump in tank, car starts now but still surges at idle.

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW E30 3 Series Idle Speed Troubleshooting

[Wayne 962]

Surging is almost always a mixture problem. Mixture problems are often caused by vacuum leaks. Although you've checked your car over again and again, I suggest that you use a smoke machine to check for vacuum leaks. I have an article on this here: http://www.pelicanparts.com/techarticles/Boxster_Tech/21-FUEL-Vacuum_Leaks/21-FUEL-Vacuum_Leaks.htm

- Wayne