Hi,

My '02 V40 has misfiring problems, I replaced a bunch of parts and it still persist.

I replaced the spark plugs, put 2 new aftermarket coils, and I still have the misfiring. It throws a code that various cylinders misfire.

The interesting part is that at idle there is no misfiring. If I take it easy on the gas pedal it is fine. Only during medium to hard acceleration it starts to misfire and the check engine light comes on.

Could it be the fuel pump or any other non-electrical related issue?

 

I was getting misfires on my 2001 V40 as well. The main code I got was P0101 (bad MAF). Then the misfire got worse & I got more codes including a bad MAP sensor. The shop replaced the MAP sensor on the outside intake manifold (under the fuel rail), cleared the code & now it seems to drive OK.

There are 2x MAP sensors (same part). One is under the fuel rail on the outside of the intake manifold. The other is in the top of the intercooler. Both are easy to get to. They are about $60 apiece.

Good luck.

 

I am getting different codes thou. Last time I checked, they were P0301, P0302, P0303 AND P0304 - all the cylinders.

 

dddDDdD55555555555555D

What kind of sparkplugs did you put in? You may want to try subbing them for genuine Volvo ones. This car is pretty fussy about plugs - so the experts say.

 

Also, are you sure that the aftermarket coils are good/compatible?

 

How can I be sure if they are good - they are aftermarket - hoped that as far as they are new - I can rely on them? They were advertised as for my model.

 

well, ideally you would have a buddy who lives nearby who owns the same vehicle who can throw some known good coils in there...not likely I know. You could swing by a wreckyard to see if they've got a set of OEM's for you. Also, is it possible that you did not put them back in in the correct order? I'm not even sure it would even start if you did that but it certainly would account for why you are getting codes for all of them across the board!

 

Changed the plugs with orig. Volvo ones and everything is resolved... can;t believe it...