'03 R50. 120k miles. New plugs and wires, new o2 sensors (x2), cleaned MAF sensor, new injectors. runs great but obd says to change the plugs and wires which i have done twice. any ideas? could it be the coil?

 

What's the error code you are getting? When my R56 started misfiring and threw a check engine light, I had a specific code telling me which cylinder it was. I swapped the coils and the error code moved to a new cylinder, so I immediately knew it was a bad coil. Replaced all 4 and then a bit later changed all plugs for a good measure as it was about time.

 

just got a scan at Oreilly. says misfire Cyl #2. the coil on these is one unit. what's a good coil to get for this old car?

 

Pull the plugs from the coil first and see if the terminal(s) are corroded. Brush them up and test again. The coil pack rarely break on these card.

 

thanks. already did that. i made them shiny and added a bit of dielectric grease but unfortunately it didnt help

 

Even though the coils rarely go bad - they sometimes still do.
Swap the ignition wires between the plugs on cyls 2 and 3 but keep the connections at the coil as they are - so cyl 2 is firing when cyl 3 is supposed to fire and vice versa.
Clear the codes and start the engine. Wait for codes to reappear - if the new code is for cyl 3 then you have a bad coil pack.

 

thanks. just tried that. new code still cyl 2.

 

If you didn't have a CEL before the plug change, I'd suggest that you may have a defective spark plug in #2. Yes, even a new plug can be bad.

 

the light was on before the plug change. i am starting to think that light will always be on. after swapping the wires it still reads cyl 2. so this suggests it's something AFTER the coil. could it be the timing chain or tensioner? there is no big rattle going on like when the tensioner is stuck. maybe take off the valve cover and check for something? i replaced the injectors fairly recently but the cars sits a lot. i drive it about 500 miles/year. maybe less