Gas cap problem??

I have a check service engine soon idiot light coming on my 2000 sl1 single
cam. I thought it might be time to invest in a obd-ii code reader but I did
have a co-worker suggest that the frequency of my light coming might be a
gas cap problem. The light comes on and stays on when I start the car but
every 4th or 5th start the light goes out ONLY to come on aging for the next
4 stops and thus the process is repeated.

He used to have a 97 tarus with the same problem and a new gas cap solved.

Any suggestions if a 97 tarus emissions system give the same idiot light
sequecences as a sl1? (both are obd-ii)