Mini Bucking/Misfiring
 

Hello all, new around here.

I have a 2011 MCS (50k miles) with an N18 engine. I recently started modding it (NM CAI, bigger intercooler) the most recent of which is a Manic Stage 1 ECU flash. The day I got it my car was fine. Second day I got a misfire buck or two with the hammer down.

It's been 5 days and since then it's gotten consecutively worse and worse until today it misfired on the same cylinder for a few seconds around 4-5k rpm and I got the yellow engine indicator half filled in and the power got cut. At that point the engine started running pretty rough. I restarted on the stock ECU map and that cleared the roughness but I still couldn't do more than 1/2 throttle without getting misfiring. I replaced the plugs and added some Seafoam today but it's only gotten marginally better.

I've emailed Manic and I'm calling the company I got the tune installed at tomorrow but I really need a solution. This car's my daily and I have a roadtrip coming up. I'm guessing carbon deposits but I have a slight suspicion it's the tune f'ing with my timing or fuel ratios or something.

Mate. I've got similar issue's with no mods at 13k miles on practically the same car 2011 MCS N18. do let us know whats happening your end.

Martyn from Manic got back to me and said it's likely a coincidence (or just the tune unveiling an underlying problem) and that his money is on the coil packs. Going to go to my local dealer and get raped on the price but at least I can have a coil pack same day to plug and play into the cylinders.

Update: Replaced the coil packs, fixed my issue.

Just a side question as I see you have your issue resolved, did you get the SPS switch so you can change maps?

Yeah I did. I figured I'd need it here on Long Island if we get a lot of snow. Then I can turn the tune off and make my car actually usable. I've already driven it in the rain with the tune on and it gets a bit hairy, don't even want to know how it will fair on ice making 220+ hp.

Ok, well if you have any issues in the future feel free to use it and switch to stock. Then you'll have a better idea if its tune related or not. Of course its not the perfect way to know if its tune related, but that option is always there for you!