Hey, I just bought a 1991 2+2 and it idles a lil weird at times. It will go up randomly to 1500 and sit there for a while, then go down to about 900 and feels as if it would shut off. It hasn't died on me yet but I'd like to get this solved. Im guessing it might have to do with the MAF but I'd like a second opinion before I go buying parts.

3 biggest idle issues on older Nissans are:
Wiring - shake the harness around under the engine bay and see if it stumbles. Look for connectors that have popped off of their little holster dudes, or stuff someone has modified.
Vacuum leaks - hoses that have corroded/cracked, or just come off of their fittings entirely.
Idle Air Control Valve - might be time to pull and clean this bad boy.