I had a similar problem with my 2000 gts. I thought it was the MAF so I got a bottle of MAF sensor cleaner and gave it some squirts, then drove it, no change. I was thinking maybe some of the oil screens but then re pulled the MAF sensor and looked at it closer under a bright led, and there it was a small chunk of gunk on the one diode in the sensor. So try the MAF first and make sure it is super clean, then go from there. Make sure you disconnect the negative battery terminal first then reconnect when done.