I have a 2001 s40 1.9L Turbo, i had a po420 code (cat code) i took care of that issue now i developed a 304 code (cyl 4 misfire). I checked the plugs. needed to be replaced, continued, changed both coils, continued, changed fuel filter, fuel pressure test and tested and cleaned injectors, code stayed in #4 cyl, noid tested the injectors and compression tested the cyl, all are good, This condition is only under a load while more then 30-50 perct on throttle, check engine light flashes and then goes out, Only thing i did notice was undercarrige is soaked with oil, on rear side of oil pan to the right of turbo. Turbo is clean and rest of car is clean,

Any help on this would be great, i havent seen anyother issues posted with this prob,so if anyone has run into it or knows how to check the turbo if that is a possibility that would be great!!!

Thanks Folks always a help to me

 

If anyone is having the same problem i found the solution out today, Even though you reset the comp after prob is fixed it is still held to memory unless you pull fuse 11/a-11 i am doing some reschearch right now to figure out if it is fuse under console in car or under hood i pulled both for 5 min and prob has gone away, i have done alot of test and test drives to see if condition was fixed and once i pulled fuses was the only time driveability problem was gone and light is staying out,,

i hope this helps someone, If anyone has more info on this dont be affraid to post it please

 

Hi Squggs, welcome to the forum.

Also, thanks for posting your solution. You did everything that I would have guessed to check like compression, etc.

 

no problem id rather have it out there incase anyone runs into same prob i guess its just the the 01 s40 that you have to do this, but i also found the connector to cyl 4 was lose but that was not the fix, it still acted up till i reset the fuse but that connector could have been a huge problem becuase of the cover on the valve cover that keeps heat in and cracks the plastic and the connector ends so everyone look out for the i have actually removed my cover to keep new wires and connector from drying out, doesnt look as good but its gonna be cheaper in the long run instead of replacing parts and chasing bad wires!!!!