For the last 4-6 weeks I have noticed that when I accelerate or lightly apply the throttle, my `09 JCW will occasionally hesitate. It feels like a misfire, accelerating steady then no power for a fraction of a second then acceleration again. The hesitation moves you forward in the seat when it happens. There is no associated noise or other tell tale indicators and it may go several days without doing it.



It does it both during hard and normal acceleration, in and out of sport mode, traction control on or off and it can happen after an hour of driving or just starting out for the day.


The only mods to the car were a change of wheels and tires about 2 weeks prior to the first “hesitation” and a 22mm sway bar a couple of weeks ago. Have a hard time thinking a set of Konig Feathers and 235/40/17 Dunlops would make the JCW hesitate. The car seems to be performing slower now but that could just be my head playing tricks on me due to the hesitation issue.


Anybody ever experience this type of problem. I will take it to the dealer but our local dealership just opened in June so I’d like to have some idea of what the problem might be before taking it in. It’s still under warrantee/maintenance but I’m curious…..


Thanks for any input.


Mitch

 

I have the exact same issue. It just feels like there is a small blip at about 3000 rpm. It usually only happens for the first few minutes the car is on.

I'm curious to know what it is too. I keep saying I'm going to take it to the dealer but I can't find the time.

 

Hpfp

 

 

I get that too.

 

+1 to HPFP as potential cause.

 

I just setup an appointment for next Thursday for them to take a look at it, I'll let everyone know what happens.

 

that could explain my emissions CEL? I though that HPFP issues started with problems starting the car?
mine only happens once a week if that so I got no hope repeating it for the dealer.

 

this has happened to mine a few times... I took it to the dealer and of course they couldn't repeat it... so they gave it a clean bill of health...

hasn't happened in a while so hoping for the best...

 

This could also be caused by carbon build-up. Read some of the post on the Sea-Foam treatment and this is also listed. You can try the sea-foam route our drive the car hard and see if that makes a difference. I had this problem early on and did both and now it's gone. Whenever I start to feel a little hesitation I know it's time to do it again.

 

Not familiar with the Sea-Foam treatment but will look into it. As for Carbon buildup, I'd be very surprised. My JCW isn't really a daily driver. I bought it to visit my GF 200 miles away on the other side of a mountain range. The MINI gets driven fairly hard, not abused, 80% of the time. If I understand Carbon buildup, my driving style should minimize the issue.

On a side note, I dropped the MINI off at the dealer last night and gave them a list of the issues I've been having. Typical stuff, sun roof won't open when hot, hood scoop melting, upper glove box rattle....the basics. We'll see what they have to has about the hesitation.

Cheers

 

Took the Mini to the dealer on Tuesday and after several calls finally got the service writer and he tells me they replaced the HP fuel Pump and had a new ECU upgrade. They had to order the scoop (still haven't said if they'll paint it red for me, original was black) and hadn't adjusted the sun roof yet but I should pick up the car tomorrow. Heading over the mountains for the weekend so it should be a good test for the hesitation issue.

I'll let you know if the HPFP/ECU upgrade solved the hesitation issue. I was surprised that they replaced the HPFP as this is a new dealership, 2 months old, and just wasn't expecting much. My bad for assuming.........

Keeping fingers crossed

 

good luck mate. be sure to keep us posted.

 

My car is at the dealer now. I should know more about it later today. I have a feeling it's going to be one of those "we can't replicate the problem" situations where nothing gets fixed and I have an extra 50 miles on the clock

 

Yep, they couldn't replicate it. And surprisingly they only put 3 miles on the car. They told me to use seafoam if I start noticing it more.

 

HPFP didn't fix mine. I am told I have the latest ECU tune. They also tried the knock sensor. My intake was also taken off and I am told everything looked pretty clean. Spark plugs were checked as well. On my car I can often hear knocking right before it cuts out.

 

I've noticed this on my JCW. 4900 miles in the odo. I've honestly just kinda chalked it up to a personality quirk of the brand as my 02' MCS used to do the same thing.

 

Seafoam completely fixed my issue.

 

did you do it same as the DIY videos on you tube? i want to try some but I am in Australia and I have never seen it here.

 

I used the videos in the "how-to" section on here.

 

*** Update ***

Picked up the MINI at the dealer Friday afternoon. Had the chance to speak with the tech and service writer directly.

Tech said he replaced the HP fuel pump, the JCW hesitated on him more than once. He said there was one "superknock" code, seemed to be old (?) but no CEL. He did not upgrade the ECU, the service writer had my car confused with someone eases when he told me that. Replacing the Hood Scoop, even painting it red, fixed the sunroof and the glove box rattle.

Now for the good part......put ~500 miles on it this weekend from in town driving, interstate driving and lots of mountain driving in the very spirited category. Not one miss or hesitation. Also, seems the power I felt the JCW had lost during this hesitation thing was back.....felt like the old MINI again.

Bad gas was never brought up, carbon buildup was mentioned as something to be on the alert for but sea foam wasn't mentioned. I must admit the new Reno Mini dealership did a damn good job repairing my car, keeping me informed and having it ready when they said they would. Nice Job.

Thanks for all the reply's and good luck to those of you battling this problem....

Mitch