A couple of weeks ago i posted a message about the timing belt being two cogs off. My mechaninc told me this when he changed it at the service (not a Volvo dealer). The reason for this is still unexplained.
-The mech told me this could happen while driving but was extremely unlikely with a Volvo.
-Searching the net for info revealed that some cars were delivered with this "flaw".
-A car geek friend of mine told me that the car could have been fiddled with in order to increase power. In theory increasing overlap could produce more power...sounds unlikely to me but if anyone has an idea, pls clarify

The GOOD part is that i have also had the lambda light / check engine light come on, most often while idling at a red light. This does not seem to happen anymore. Thus my advice to you who has the same problem (misfire codes on all five cylinders and check engine light) is to check your timing belt! I have no good idea why this would produce a misfire code but since this is the only change i have done...

Hopefully, this will help someone with a similar problem. I woule like to hear from someone that has an explanation though. :)

/Peter
850 GLT 2.5 20V 1996