Lots of Misfire Codes for Every Cylinder
 

Just purchased a used 2005 Volvo V50 T5. It runs great. This morning, however, I noticed it running a little rough at idle but still performed just fine. Then, a little later, the CEL came on. (I can't tell you how frustrated I was especially after I had done so much homework and took this to a mechanic before buying this. I bought it yesterday!)

Here are the codes:

P0300 Random Misfire Detected
P0300 Random Misfire Detected
P0302 Excess Emissions Level of Misfire Detected on Cylinder No. 2
P0304 Misfire Cylinder 4 - Catalytic Converter Damage
P0305 Cylinder 5 Misfire Detected
P0301 Misfire - Cylinder 1
P0303 Cylinder 3 Misfire Detected

My assumption is that not all the injectors, coils, plugs, and wires, went bad all at the same time.

What I am lead to believe is that it could be one of the following:

• Camshaft position sensor
• Fuel pump getting weak
• bad fuel filter
• mass air flow (MAF) sensor bad
• Leak in the intake manifold gasket
• Fuel pressure regulator (does my car have this?)

My other guess is maybe the gas was bad?

Does my car have an EGR valve?

From your experience, what the heck could be going on? Am I on the right track? What would you start with?

Have you checked the condition of the coils?

I think you are on track - but you should check the conditions of the connectors into the coils first = look for looseness or cracks in the insulation for the wiring to the coil packs. I'd also throw "check fuel pump relay" on your list. Did you try clearing the codes and see if the CEL came back?? Also inspect vacuum lines etc. Anything change with the temp gauge?

In my experience I always check the condition of the actual coils first nto the wires. Check for cracks on the coil under the rubber boot.

Because it is 7 degrees out this morning and don't have a heated garage, I will take this into the dealer (though I don't want to). I will have them check those things you mention specifically plus some others. I will let you know as soon as I hear back from them.

Resolved...kind of
 

Well, took it into the dealer today. They ran all of their fancy diagnostics plus inspections and could only come up with a weak battery that needed replacing. Everything else seemed in good order...

BUT!

As the technician was topping off the coolant he noticed a lot of pressure as he released the cap on the reservoir. As he released the cap he smelled exhaust, too. This can only mean one thing...blown head gasket.

I only owned the car 1.5 days before taking it back to the dealer asking for a complete refund. I got the refund and I'm no longer a Volvo owner. Don't know if I will go back to being one especially after all the homework I had done and good things I had heard about the reliability of a Volvo. Perhaps I just had a lemon.

You mentioned that coils and plugs were changed, what about the wires that lead from the coils to the non-coiled plugs? If I recall, coil 4 runs 1 and 4 and coil 3 runs 2 and 3. Given you have issues with 2 and 3 and the coil is ok, I suspect the cable to 2 is bad or the harness connector to coil 3 has an issue. It is a common problem with these connectors as they are subject to lots of heat. Open the connector and remove the 2 contacts, inspect the wires/crimps and connect direct to the coil, see if anything changes.
https://cimg6.ibsrv.net/gimg/volvofo...c79173a82c.jpg

I'm thinking that a reply to a 4+ year old thread to a guy who no longer owns a Volvo is probably a waste of typing. Errr, sort of like this reply. ;-)

lol, my bad, was replying to a recent post and some ended up posting on this thread