P0102 and intermittent rough idle on start.

1999 Lumina 3.8, 100,000 Miles.

Car will occasionally sputter and shudder on start up(cold or warm). Always sets P0102 MAF Circuit Low Input code while this is happening. This code also sets while the car is running and starting normally.

I pulled out the MAF and sprayed the small wires with contact cleaner and nothing changed.

I also unplugged it and drove around for a while and the only difference I noticed was a slightly higher idle (1000RPM). It still intermittently idled like crap on start up.

I removed the climate control vacuum line off the big brake booster line and hooked up a vacuum gauge. When the car is idling fine it's a steady 21Hg.

When the car is sputtering on start up, it reads 7Hg and slowly rises to around 20, at which point the engine revs up, the gauge hits 24 and comes back down to 21. Everything works fine after that.

This problem happened maybe three times a year until I changed the spark plugs a few months ago. Now it happens all the time.

All the vacuum lines seem ok.