Happy new year all!
Long time lurker here, and today I would very much appreciate some help!
The engine emission light has come on permanently, on my 73,000 mile 04-reg Vectra SRi 2.2 16v Direct. I plugged my code reader into the car and get the following when selecting "Total Number of Fault Codes":
P0304-01 Cylinder 4 Misfire Detected
P0301-01 Cylinder 1 Misfire Detected
U2139-71 CAN-Bus CIM Message Range/Performance
B3901-00 Wrong Environment Identifier Received
For a couple of months or so, the engine has sounded a bit rough, especially when just parked and left running, but the emission light first came on the other day on the motorway. The engine lost power, and the car slowed from 85mph to 70mph and wouldn't accelerate any higher, so I pulled onto the hard shoulder and switched the engine off. Two minutes later, the light didn't come back on but the engine sounded pretty rough, and felt weaker than usual. Driving seemed otherwise okay (I was able to complete my journey and make it home afterwards).
Yesterday, when pulling away from some lights, the car accelerated very slowly and was extremely weak. It would barely move. The emissions light started flashing, which I know (from the manual) means to slow down until it stops flashing. I was only doing 15mph anyway, though.
The light is now permanently on, and the engine sounds awful. There are also random "dead spots" during acceleration. Any suggestions on what might be the cause? I would love to be able to fix this myself (wouldn't we all!). I would make a bit of a noob guess from the "cylinder misfire" codes and suggest it was the spark plugs, but they were replaced 15,000 miles ago (allegedly) by a dealer at the car's service last March.