We have an 04 Mini cooper S JCW. For the most part the car runs great. Every now and then sitting at idle it drops and idles very rough. If you tap the gas a couple of times it comes right back.

My girlfriend now says it feels that the car does not have the same power all the time.

I am thinking fuel filter? Any other ideas?

Does any one know what the fuel pressure is suppose to be?

 

Is it on start up in the morning

 

It does a small cough then starts right up. It also will do it all day long on and off when it comes to idle.

 

Mine will do it on start up for 2 seconds and then she levels off. It just started to do it

 

Just a guess.....
Do you have any mods??
On a JCW...the sparkplugs need to be changed often..(service 1+ 2)...that might help.
Sea-Foam seems to help out many folks with some problems caused by carbon build-up, or dirty sensors...get the spray or liquid (not the deep-creep version) and spray/pour it into the PCV hose that you pull off the vent, while the car is running...then shut the car off...wait 5-30 minutes...then start....idle till there is a bit less smoke..then take it out, and run it hard till the rest of the smoke is gone. It might help a lot. There are many threads on it. One warning...you might throw a code..so you might need on ODB reader to clear it...(some auto places will do it for nothing..Autozone, etc).
Beyond that, there are a tons of things..my recommendation is to ensure all basic maintenance items are done (plugs, air filter, wires if over 100,000...and check the terminals on the ignation coil...they sometimes corrode causing issues...and then see if you still have a problem.


Most pulley folks use JCW plugs....They are one step cooler than S plugs...since you have a JCW, you already have these!!

 

I have changed my filter twice now. Once at around 55K miles and then recently at 95K miles.....I had that idle dip before too. I blip the throttle and it goes away. I change my plugs often, and now run one step colder NGK Iridium plugs. That seems to have help as I noticed it only has happend on two occasions in last 6 months since switching over.

When last checked my FP was:

At Ignition Position 2 - 52
At idle 42
At High RPM's - 62

 

For those with occasional rough idle... this issue is due to a recall on the computer. My old '02 MCS started having occasional rough idles after the computer was reprogrammed back in November '05. It started the day I picked it up from the dealership. I was told that it could not be reversed once updated. My guess is the idle circuit fuel mapping was changed.

One point to note... don't buy Hess gas. Our local club had a discussion about this awhile back. I would go start my old '02 MCS in the morning. It would immediately die after starting up. Start again... no problems. I attribute the issue to whatever additive mixture they are using.

 

Sadly, Ellie started doing this today. I was at a light and when it was my turn to go, I put the e brake down, put it first and couldnt go. I started her up again and as long as I was on the gas it wasnt a problem. Once I dipped below 1RPM, it would shake and stall out. I just had the transmission replaced 2 months ago. I spoke to the guys who did my trans and they dont think its related to that. Since getting Ellie back (I didnt have her for 5 months), ive put nothing but 93 octane in the car. I used to cheat sometimes and put 89 octane in it.

As of right now I am currently waiting on a phone car from a shop near me that works on MINI's. I dont know about anyone else but im borderline about to cry, ive already put 3800$ into the car and cant afford to put anymore money into it.

 

As a suggestion, put a bottle of fuel injection cleaner in the fuel tank on the

next fillup. You may have some deposits in the injectors resulting in the rough idle.

 

The SINGLE most important thing about owning a MINI that will not be a money pit....get to know a local shop that works on lots of MINI's....they are around.....sometimes an hours drive....but for most it is similar as the drive to the dealer....but it will save you big$$$ in most cases. Most shops that work on MINI's are well known in this community, and they often have a following.....most BMW shops can work on MINI's.....but I have my fav...a MINI shop that can work on BMW's!!
Sadly, Ellie started doing this today. I was at a light and when it was my turn to go, I put the e brake down, put it first and couldnt go. I started her up again and as long as I was on the gas it wasnt a problem. Once I dipped below 1RPM, it would shake and stall out. I just had the transmission replaced 2 months ago. I spoke to the guys who did my trans and they dont think its related to that. Since getting Ellie back (I didnt have her for 5 months), ive put nothing but 93 octane in the car. I used to cheat sometimes and put 89 octane in it.
Sorry to hear that...some earlier cars can get pretty spendy as they age...I hope you are still not taking to the dealer....Good gas is a good thing, but can't undo many miles/years of neglect....but it is a good way to ensure more damage is not done!
Welcome to NAM Minicoopergrl!!

 

I have an 05 r53 and had the exact same problem. I bought MSD ignition, NGK wires, and NGK plugs. Almost 200 bucks worth of stuff which I planned to do anyhow. None of it changed the rough idle and at times weak power and even some hesitation when cold. Couple of months went by and I had given up on trying to smoothen it out. Then my service engine soon light came on and it was a too lean and emissions code and a gas cap code. Picked up a new gas cap at Oreilly's for 30 bucks and problem solved. No more hesitation or rough idle.