Hi all i have an intermittent check engine light coming on every now any again, i drive up and down to work every day and the check engine light wouold never come on, but when i,m home and i,m driving around my local area the engine light would come on,
What would cause it because of all the starting and stopping when i,m driving through my local area with traffic, because when i drive to work i drive straight up and straight back with no real traffic.

Iv had the fuel pump changed 10k miles ago the thermostate changed 7k miles ago and the trottle body changed 5k miles ago
i have 65500 miles on clock and its a 2001 s40 gdi 1834cc. and sometimes when i start the engine she will not go above 4000rpm only every time i start the engine, when i go up to 4000 again its got.

please try help anybody
these volvos are a nightmare

 

Maybe it is misfiring?