My 03' R53 started doing some weird stuff on the way home from work yesterday. When ever I start getting on the gas, and I start building boost.....the power from the motor will cut out for a second, almost feeling like a misfire or dead cylinder. It didn't do it every time I got on the gas, but most of the time it would....it would bobble and skip a beat or too. The plugs and wires aren't that old...but it sure does feel like some sort of misfire.

I don't have any codes ...so I'm at a loss. Should I just go ahead and change the plugs and wires, or could it be something else?

 

Could be the bypass valve

if you go on full throttle straight away do you get any hesitations?

 

If it was the bpv....I would think that I would lose boost, and I'm not. It's maintaining boost when it does the missfire/bobble.

 

Replace the front map sensor.

 

I had an issue with a misfire under load; actually twice, and changing out the coil fixed it. If you have an extra coil, just swap it around and see if that helps.

 

I was going to say this too. Check the terminals for corrosion too possibly .

 

I have a misfire/hesistation under heavy load as well. Went to swap the coil out today and 2 of the 4 bolts were stripped (on the valve cover side) so take it easy when removing and tightening the coil pack bolts.

 

Yes.....it feels like a misfire. I will take a look at the coil. If it's got a lot of corrosion on it......should I just get another oem MINI coil, or is there a better aftermarket "performance" option out there?

Thanks guys!

 

I think the consensus of the knowledgeable people on this forum is that "performance" coils do not offer any improvement and just stick with OEM.

 

Check your plugs as well, I had one that had microcracks from the factory, it took me a long time to diagnose it as I "knew" that the plugs were good as I'd just changed them....It had an 1/8" wide carbon track all the way down the insulator-obvious once I pulled the plugs.

 

Turn off your DSC at startup and see if that helps.

 

I don't think it's a traction control issue......it will do it going 70mph down the highway sometimes. But I can give it a try.

The car is 17years old, and has 180K miles on it........The current plugs and wires have around 30,000 miles on them....and the coil is the original. I went ahead and order new plugs, new wires, and a new coil today....I'm hoping that will cure the issue.

 

Indulge me and throw just the new coil on and see if that helps the situation. Crazily I had a coil fail on my Mini recently, so i bought a brand new OEM mini coil, and that too failed within 3 weeks, and then the replacement finally cured the issue. Basically would misfire under load and when it reved above 4.5k rpms.

 

Yep.....I think I will do the coil, then take it for a drive. Then do the plugs...take it for a drive. Then wires....and take it for a drive.

I'm curious to see what is causing the actual problem.

 

My first guess would also be bypass valve, other things are fuel delivery/ignition (most likely). Good luck, following this thread!

 

I have a boost gauge, and the boost is not dropping off when it does the bobble/missfire thing...so I don't think it's the BPV. I'm guessing ignition also....I should know next week when my parts come in.

 

Agreed, then the BPV is alright.

 

***UPDATE***

Well, my new coil never came in on Friday like it was supposed to, but I did get my new NGK plugs and wires. The terminals on the old coil were all corroded and looked horrible. I cleaned them off, installed the new plugs and wires, and so far...the car is running great. Not sure if I will install that new coil when it shows up, or just return it. So far so good.....

 

I would install it for peace of mind, keep the old one as a spare unit.

Add a small dab of dielectric grease on the connectors > https://www.farmandfleet.com/blog/wh...%20connections.

 

Glad you got it sorted! Corroded connections would definitely do that!