Boxster problems.Need your help please!!

[boxsterkid]

I have a 99 boxster tiptronic with 21000km.I haven't drove it for 3 month.I finally took it out a few weeks ago and at a red light the check engine light came on and the car just stalled.On another occasion another red light the rpm went down and up again as if the engine were strugleling.On the highway sometime,the check engine light would light up for a second,feel a small jerk and light goes off without stalling.Only stalls on a complete stop(on drive and park).Sometime I don't get the problem for a few days.I brought it to the porsche dealership.They kept it for about a week because it had not stalled on them.When it finally did,they checked the codes and said 2 relay had to be change.Made the repairs,2 days later the same problems comes back.So before I bring it back to the dealer.I would like you advice on what may be wrong.I think it might be the o2 sensors or the fuel pump.I do not wanna pay for other costly repairs I don't need.

Thanks for any advice guys.

[Loren]

Sounds like MAF sensor to me but it would be nice to know what the codes were.

[boxsterkid]

I will ask them call them up on monday to find up the codes.

[Viktor]

This may help, I had a similar problem with a MZB. After all of the tests, many days and $$, it turned out to be a bad soldier joint or connection in the fuel pump relay. Good luck!