Question about my 2004 Nissan Sentra Service Engine Soon?

I'm getting some mixed results on that code (one site doesn't even list it) You best rescan the car and make sure that is what comes up.

P1273: Accelerator Pedal Position Sensor 1

Yeah, the MAS is normally the one to trigger a check engine light, but the code is stated above.

this code indicate the engine is running lean (too much air not enough gas). look for vacuum leak. after that, you need to reprogram the computer with a new improve software ( number NTB04-126). this is done by the dealership only. your vehicle might qualify for warranty. cost about 150.00

you need to consult a library and find a copy of Haynes engine management and fault codes book?...if not put it on the analyser at your local dealer...

List of all trouble codes....

http://www.obd-codes.com/trouble_codes/

maybe it wasn't the old spark plugs that was the problems. i'd go get a technician to read your code.