ok, here it goes. I have an 04 545 and has about 99,000kms. So I figured its time to change the plugs. Had been deciding on which plug to get and went with Bosch IR Fusion. Looked up the DIY here and thanks to the members, it helped a lot. Now, after changing them, the engine started to putter and running rough. Dont know if its the plugs or what and sounded like a misfire.

Bought a scanner and it first said, cylinder 5 misfire. So I changed that one and no change on and the scanner still said cylinder 5. So at this point I have been messing with car for about 3 days now and getting really frustrated. So I decided to put all the old ones back since I did not have a problem to begin with. Did that and running a little better but still not normal and scanner says its a random misfire now, ugh.......

Called a mechanic and said it could be anything and wanted to work on my car. Now to save me alittle money, should I just buy the plug that originally came out of my car and put them back in. Will that fix the misfire issue. Car was runnning great before I attempted to change the plugs. By the look of the plugs, it needed to be change anyways.

Thanks in advance for any input or advice. Just want to try everything first before forking up big $$ to the mechanic.

 

I'm hardly an expert, but it sounds like something may have happened to your wiring during the tune-up -- especially since you still had the same problem when you switched spark plugs for the fifth cylinder. Plug spark plug quality control is very good so it'd be highly unusual to get a defective plug.

I'd double check the wiring for the fifth cylinder. (Is it twisted. pulled, loose etc?). Make sure that the ignition wiring is properly plugged into the ignition coil. Also inspect the ignition coil. Make sure the coil's rubber boot is not cracked, and that it is seated properly in the cylinder.

If you don't see anything obviously, then I'd immediately get your car to a mechanic.

 

Thanks for the info. I actually exchanged those plugs for NGK iridium and put them on and still the same. Something must of happen when I had the original misfire. Well now, got the car towed to the mechanic and will advise me tomorrow. Wish me luck!!

 

possibly a coil got damaged somehow. you could try to swap coils with different cylinders to see if your scanner detects a misfire on another cylinder.

 

+1 before you did the tune up cylinder 5 coil was probably weak and once you changed the plugs the misfire became more apparent. check those coils..you may have a weak coil...and those coils are very expensive...even top quality after market...but i wouldnt put those in.

 

Hi
My car did missfire as well, in the workshop now changing all ignition coil some was only 60% good they say so better change all of them
Price in Thailand 16.000Baht= 490$

 

Yea, I took to the dealer and they said it was only one ignition coil and it was the number 5 coil. They replaced the coil and kept my new plugs and works like it did before. I think at the next change, I will change all other coils.