My car is at the mechanic. I took it in because the check engine light came up. Upon reading it, it is due to misfires. After changing all the plugs, doing an oil change, fuel filer, and airfilter, the engine is still misfiring. The misfire is not all the time but it misfires intermittently on different cylinders. Has anyone seen this before? We even sucked out all the fuel and put in new one. We are at a lost. Any insight will be appreciated.
Although this is very hard to diagnose from afar if we are talking about a late model 01-05 6 cylinder BMW it may likely be bad ignition coils or ignition coil harness lead wires. A pretty common problem on these cars. It may be time to find a BMW technician either at the dealer or independent that has seen this before. Good luck and enjoy!
Did the tech change the plug boots? I have often seen one or more bad coils, but not usually all of them. I believe there is an SIB on the harness, though, and it is not too expensive, because it is a small harness. How many cylinders have misfires? What year and model? Hard to daignose if we don't know which motor.
it is a 2001 530i with 100K. I thank both of you for the information. Yes they changed all plug boots (I got them from autohausaz) as well. This is an independent guy who works on nothin but BMWs and Mercedes. I guess if he does not find the issue, I will have no choice but to take it to the dealers. I await your feedback and thank you
First of all, if you have a reliable Indie, the BMW service ppl won't be able to diagnose it either IMO. My Indie (Bavarian Professionals in Berkeley, CA) ONLY works on BMW's and if they couldn't diagnose my ride, no way would I take it to the stealership. I have heard of a similar issue and it turned out to be a couple bad coils so I wouldn't rule that out...did you ever find the problem?
I had a similar problem with my 540 and it turned out to be leaking valve cover gaskets. Oil had filled the spark plug holes causing misfires. I don't know anything about the 6 cylinder engines on these cars, so my idea could be completely useless.
Couldn't hurt to check since I had the same issue with leaky valve cover gaskets (a common problem on these engines) but it didn't cause any misfire. Were your plugs loose too? That would account for the misfire since the oil could then leak into the cylinder via the spark plug, which would foul the plug PDQ as well.
