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