Good Day everyone, I just bought a 2000 S40 and has 155000, the car run good, is rough to start(takes about 5-8 second to just start, like if it was not furl, but the pump works), I heard is the fuel pressure regulator that I need to replace, but that is not my only problem, yesterday the CEL came on with the code P0303 misfire cylinder 3, so I check the coils and replace the spark plugs, but the code came back again, does this has anything to do with the long cranking? should I replace the fuel filter since probably the previous owner never did? please give me your expert advice, thanks

 

Had a hard time finding this one which turned out to be a bad connection inside the fuel injector connection-used Ease Diagnostics on laptop together with Snap-On lab scope and spark tester attached to windshield wiper all at once to find. Recorded everything then went back to trigger point and found the injector was "missing" under load, higher RPM and the warmer it got the worse it was. took 3 days to find.Hope this helps someone else.

 

So, after you isolated the problem, what was the solution?

 

The fix was to take the connector apart, repair the loose wire to metal connector, tighten the "squeeze" where the connector holds on to the injector and reassemble the connector.