My VT Series 2 V6 Commodore has an intermittent miss. No error codes are coming up, and I have replaced the plugs, leads, coil packs and DFI, and cleaned all the connectors on MAF, TPS, IAC, and CAS. I have also checked the purge valve and hoses for vacuum leaks, cleaned the injectors with a treatment and checked the temp sensor for accuracy. The misfire occurs mostly when cold, and it will occasionally stall at idle, for about the first 20 minutes of a drive. It stalls maybe three times in 20 minutes; there could be a heavy misfire from idle for three seconds, clearing as you accelerate, and the odd single misfire. I can rule out the CAS ? if that were misbehaving it wouldn't run at all. The misfire was a sudden onset thing, so I suspect it?s a failure rather than a wear-out situation. The only thing that I can think of is a transient blockage in the fuel line or a bung injector that works ok when hot. Any thoughts?
I would put my money on the Crank Angle Sensor, even though you are willing to rule it out. It does sound electrical and the CAS is often the culprit in these deals.