Well hello there, recently I started having some issues with my '05 Cooper S (183,000 km/113,000 miles). When I'm driving on the highway at cruising speed, I'll get some nasty misfires like behavior, but without the codes. My recently installed AEM Uego wideband alternates fairly quickly between 14.2-17 when everything is fine and dandy, but when my issue is happening is goes straight to 12-10.

My boost gauge, in vacuum at cruising speed, will jump around 2-3 bars (lines on the gauge, not the measurement unit) when it start doing the problem, so it's very noticeable. The engine is clearly missing, but it's something the ecu can't see apparently. I have yet to do a compression test, but decided to check if someone had a similar problem. Sparks plugs are new, plug wires are new and the problem is still there. I've had the same mods on the car since 2011, minus the header and exhaust done last year. Thought the bypass valve was acting up, so I put the oem back in, same issue. Running rich when flooring it, but won't have any misses.

Mods are:

- 15% pulley.
- JCW 380cc injectors.
- GP Intercooler.
- Detroit Tuned BPV.
- DDM air intake.
- NGK BKUwhatever, same 1 step colder I had for the last 6 years.
- OBX header with 2.5" exhaust.
- Always running 91, can't really get anything higher on the go around here.

Thanks for your inputs.

 

i have the same issue on my mcs 06.. im from qc aswell..


brought it two weeks ago. 170,000km. rallie edition.


havent changed anything yet.. execpt the f** dipstick , and oïl / filters.


, on relax drives, no issues.. if i floor it ( any gear , any speed ) i dont really feel any missing.. but if i let go the gas pedal 1/8in, it starts to do it.


i will do the ecm reset this weekend.. if that helps. i run 94gas...


write me up i you've found the source of the problem..

 

Pull the plug wires from the coil pack and see if there is any rust. If the electrodes are steel you have an OEM type unit as many of the aftermarkets have brass that will not rust.

I was getting skips on my R53 while accelerating right around 3,000 rpms. It was the coil. If you change it, be sure not to lose the rubber donuts that are both on top and below the stud bolts. Also be sure not to over tighten as you can break the valve cover.

 

A little update to my problem... New OEM coil pack and the issue is still there. It wasn't going to hurt to replace it as the car is 13 years old and almost at 190,000km. Compression test done last fall was fine, if I remember correctly, cylinder 2 was a bit lower than the other 3, but well within margin. Basically, I have a new coil pack, new plugs and new wires.

Since I'm going rich when the issue occurs, I have either too much fuel or not enough air for some reason. At this point, I'm thinking about checking the fuel pressure and possibly replacing the fuel filter while I'm on the fuel side. It's only happening at highway cruising speed, normal city driving or flooring it is fine.

 

 

Also forgot to mention that it start doing it after 10ish minutes of driving. From cold to almost mid-way thru my ride to work it's fine, then it start cutting.

 

bump for somebody with a solution ?


i changed the fuel filter last week, helps a lot with the loss of power from the years.. but still the problem is present.,

 

My crank pulley started making a funny noise and being wobbly, so I've replaced it with an ATI and I've replaced the fuel filter today. I'm at the point where I'll just drive with my OBDII scanner plugged to check basic datas and find the culprit because the ecu refuses to throw a code even tho it's cutting out badly at cruising speed when warm...