1: Plugs replaced car appears to be running great. Drive it around for a day without issue.
2: Brake pads need replacing so replace brake pads
3: Test drive after pad replacement, no issues
4: Come back an hour later, drive car and immediately have misfires and issues, code reader has multiple codes, P0300, P0304, P0305 and P0456.
5: Move plugs to different cylinders and the misfires follow the plugs
6: Decide to replace all the plugs (again and go from Bosch to Champion), everything ran great. For a day. All of a sudden last night we are now getting a misfire on cylinder 6 again (P0306).
7: Moved swapped coil from Cylinder 6 to 1, misfire stays on cylinder 6 (P0306). Move plug to cylinder 1, misfire changes to cylinder 1 (P0301).
8: Replace plug in cylinder 1 (this is now the 3rd new plug) and it all runs great again.
9: Drive a few more times, and now we have a new misfire in cylinder 6 (P0306).
Try putting the OEM plugs in it… Did you match the old plug parts number with the new plug part number… The Bosch Part# 12 12 0 037 582 (ZR5TPP33) is the OEM plug…
Also where did you buy the 1st Bosch plugs?? online or at the BMW dealer or at a local parts store…
Did it have a cel on before you replaced the plugs?? What was the reason for replacing the plugs? mileage or running bad etc??
First set of plugs were the OEM plugs you indicated above
Rock Auto
We were having some rough idling and it was past time that the plugs needed to be replaced (we bought the car used about a year ago and talked to the original owner who said he hadn’t replaced the plugs ever).
Maybe it is time for a compression check while you have the plugs out. You could be getting counterfeit spark plugs, even from RockAuto, but the compression test will confirm or deny the problem is spark plugs and not weak cylinders.
Counterfeit parts even from Rock Auto? I do not believe that. Also, even if counterfeit, one would expect the parts to perform their intended function, just as a counterfeit brand-name watch usually tells proper time, and a counterfeit brand-name handbag usually zips closed and works to carry stuff.
I would expect a counterfeit spark plug to screw into an engine and ignite the fuel and air mixture just like any other spark plug. And while people might be making counterfeit Bosch or NGK spark plugs, no one is making counterfeit Champion or AutoLite, or any other budget brand.
I still think the underlying problem is either related to fuel or compression. At this point, it could be anything from a clogged fuel injector to a burned-out driver IC in the PCM to one or more cylinder(s) with inadequate compression.
No BMW experience, just a drive-way diy’er, but it sounds like a coil problem to me also. On modern car engine designs, as the plug gap increases with use the computer will correspondingly increase the voltage to the coil. Eventually the coil overheats and is damaged. I’m guessing the prior plugs may have been installed a little too long, the gap got too wide, the computer increased the voltage, and the heat damaged the coils. Common sense says it is best to purchase the replacement oem plugs and coils at a BMW dealership. Doesn’t guarantee they are not counterfeit, but increases your odds.
Why would you think that? Even if the plugs were close to correct, many cars are very picky about the plugs that are used. Some cars just will not work properly with plugs that are not tbe OEM supplier… German cars that will not work properly with anything but Bosch. Japanese that reject anything but a Denso.
In the early days of AliExpress, the Chinese Amazon, there were auto parts sold by part number only. I, and others, suspected they were from the OE’s Chinese partners reject bins. I.e. parts not meeting spec but they look OK.
A compression test is a great idea…
Did you check the gap on the plugs??
Did you check the gap on the plugs after the misfire started and you moved the plug to a different hole?? If it closed up some, well you have issues… lol
Possible the ceramic insulator on the spark plug is cracked… I would get the plugs at a local Napa, Advance Auto/Car Quest or O’Reilly’s…
Very common problem on these, I spent days the first time I saw this- the way the engine shuts down cylinders to keep emissions in spec causes some strange symptoms when trying to see what’s happening. Because it shuts the coil down it over loads the others and they usually all fail within a month. As old mopar guy says just replace all the coils.
@Darron …tx for the informative post. Just curious, why would turning off the spark to some cylinders (apparently normal for this car to reduce emissions) , why would that affect the coils on the other cylinders? Also, do you have a recommendation to the OP for the replacement spark plug & coil brand and source?
It’s the way it monitors ignition/ quality of fuel combustion-part of it is crankshaft speed on each cylinder fire ( to slow or fast it changes the mixture-timing to clear it ) if the cylinder either side or next to fire are not 100% they log an issue and they start getting the fuel/ timing messed with. The test on the BMW system would say if replacement of the parts on a cylinder hadn’t rectified the problem the repair should be carried out on adjacent cylinders. As for parts I’m a bmw tech so all the stuff I work on has genuine parts, I’m also in NewZealand so we have different auto stores unfortunately, I’m sure most known brands should be fine
