Code 1215 - Surging Idle after performing a bunch of maintenance

[wake74]

The new to me 95 318ti (M42) had a bit of a rough idle, and lots of obvious deferred maintenance.  This weekend, I did the following:

• Remove upper / lower intake
  Replaced engine temp sensor (the rear gauge one, albeit still doesn't appear to work)
  Cleaned fuel injectors
  Cleaned ICV
  Replaced both hoses into / out of the ICV
  Replaced the small vacuum hoses going to the fuel injectors
  Replaced water pump (that was a MAJOR chore)
  Replaced thermostat
  Cleaned throttle body with cleaner
  Replaced serpentine belts
  Replaced fuel filter

Took a bit to get the car to start but it won't idle smooth at all.  Surges from around 500 to 1,000 RPM.  Runs above that, but not too smooth.

Engine code is showing a 1215, which is Mass Air Flow Sensor.  I didn't do anything to that at all.  The MAF is plugged into squid. No engine codes previous to this tear down.

Thoughts?  After all that work, I was hoping to have a better running car, not a worse one.

Thanks!

Glenn

[monty23psk]

Sounds like intake leak, its possible one of the gaskets for the intake did not get a good seal.

[timmy.chisholm]

You can find any vacuum leaks by spraying around with a can of brake cleaner. Your engine will increase in RPM if you  spray the location of the leak (if there is any). Maybe you just forgot to tighten one of the clamps around a hose, happened to me leading to the same results.