My 2010 Holden Barina Spark runs rough due to piston misfire. I've had various mechanics (including a Holden dealer) try to fix the problem. They've replaced all four ignition coils twice and individual ones two or three times (11 new coils in less than 3 years at least). They've replaced spark plugs, fuel injectors and who knows what else. Now they want to replace more coils. The typical scenario is they do the computer scan, say cylinder four is misfiring, replace the coil and then say cylinder three (even though that did not come up on the original scan) is misfiring and needs to be replaced, and so it goes. Is it possible that there is an underlying problem and that they are only treating the symptoms? Is there an advice line where you can refer these specific problems? This has cost thousands and they are just guessing. The current mechanic has had my car in his shop for over two weeks. One mechanic said it would cost them a million dollars to find the problem. Would it be better to take the car to the scrapyard?
Yes, I would suspect that there is an underlying issue that hasn’t been addressed. I would be having a compression test done on the engine to see if it could be a blown head gasket or something similar.