P0300 Random misfire detected
A. Random misfire
B. Random misfire, TWC damaging
P0301 Cylinder 1 misfire detected Cylinder 1 misfire, TWC damaging
P0302 Cylinder 2 misfire detected Cylinder 2 misfire, TWC damaging
P0303 Cylinder 3 misfire detected Cyilnder 3 misfire, TWC damaging
P0304 Cylinder 4 misfire detected Cylinder 4 misfire, TWC damaging
I checked the plugs they are the expensive quad electrodes so I do not think that is the problem. it had a cracked hose coming off the oil separator that I changed and test drove the car and now the sc is working but the car was still not running right and cel came on I scanned it and got p0301...I am at my wits end with this car!!! Anybody have any ideas??
Thanks to Leapyfish for providing some reality based on the facts you had already given.
My K40 diagnosis was based on symptoms, not on reported codes, and so missed that important point.
And having had a good result, I was happy to share it (even if it was not relevant). Hope this didn't mislead you too much.
However, since the K40 is so quick and easy to pull out and resolder, I will be sure to include this in any engine diagnosis.
Comments about the plugs; it may be that the plugs are not to the correct spec.
At one point, NGK produced "V" plugs that had a paladium tip plug, with a fine central electrode (for improved gas flow around the spark), which I fitted to my Vauxhall Nova with expectation of great benefit. After a short period, I found they mis-fired, so pulled the plugs, only to find the central tips had completely disappeared on all four plugs, and the fact the engine ran at all was based on the CDI being good enough to drive a spark across a 4mm gap (compared with 0.5mm nominal). Back to the BPR8ES (from BPR8EV) and normal service was resumed. Low tech suited that engine.
So do check the spec (example based on NGK nomenclature "8"s); if they have fitted cold plugs ("7"s) that will run better when cold, but will overheat when hot, resulting in pre-ignition.
If you have a heavy right foot, you might be able to justify hotter plugs ("9"s, that run better in a hot engine) but nominal spec is typically good enough.