2001 S40 Misfire problem

goldenreed · Post by **goldenreed** » 19 May 2010, 10:37

My 01 S40 has a consistent idle stumble and hard acceleration problem. I get misfire #2 and #3 codes (302 and 303). It is worse is cold/wet weather at start up (especially when in drive) and also consistently stumbles on hard turbo acceleration. Otherwise around town and on the highway it performs fine. I've replaced the plugs, swapped the coil without moving the misfire code location, unplugged, cleaned and swapped the injectors and tested the spark on #2 and 3 with an inline spark tester light and that shows good consistent firing.
I am thinking maybe MAF but why only #2 and 3 cylinder misfires? Is it worth trying to clean it or just replace. i hate to spend $200 without a firm indication or code.

Thanks

jtz54 · Post by **jtz54** » 10 Jun 2010, 16:01

Plug coils go bad causing this problem. I had same thing. Fixed by replacing the coil. If you replace one at a time you can figure which was the bad one (if you only want to buy 1 new one). Mine was only missing at WOT.