Lately for the past 2 to 3 weeks when I startup in the morning, and try to take off after say a few seconds (creeping out of the garage, in drive and foot on break --auto trans.), the engine stutters and/or stumbles - acting as if it is going to stall, but doesn't. I haven't paid too much attention to the RPMs (yet), but I noticed that if I shift to neutral (automatic), the engine picks up, if I put it in gear again D or R...the stumble/stutter continues for a few seconds until it goes away on its own.

Anyone else having this issue? This is on a 2018 F60 JCW with under 15K miles. I have found if I let the engine idle for longer before taking off, I don't see this problem. In the past a can of BG 44K resolved similar issues on other cars almost right away. I tried that with this car, no change so far.

My thoughts are vacuum leak, carbon deposits, fuel filter, vanos?, other sensors, high pressure fuel pump?

I suppose I could take it to the dealer for them to diagnose...but I hate doing that since these types of problems seem to elude them.

Any suggestions? Anyone else run into this?

 

That's killer. and you have those cool new wheels ! I don't think it would be a vacuum leak , cause that would occur all the time, Your fuel mileage is good ? Do you run gasoline with ethanol ? I think its that ethanol. Its not really good for the engine. It draws moisture, and with that ethanol, its possible it could cause that stumble at startup. If you have a gas station that has real gasoline, with no ethanol, start buying it there and see if by the third tankful if the stumble/hesitation is gone.
That crappy ethanol ruined a good motorcycle I had. eat the gaskets and really left crap in the bowls on the carbs. I am still annoyed by that and it was ten years ago.
I try to only run gasoline without ethanol, in my Triumph, Lexus, both Jeeps & the Mini. Its 20 cents more per gallon. Only time they may get a load of ethanol gas, is if I'm away from home and there is not any real gas is around.
I don't care how much it is, they are not getting me again. My old 98 Jeep is from a time before forced ethanol. The Lexus has had two recalls for replacing fuel rails and gaskets around the fuel sensor, and the fuel line. I know it was because of ethanol. pure_Gas.org
I think it will make a difference. I can't remember our Mini ever having any hesitation on cold mornings.
Its just something to try before you have someone tearing into the engine bay. It certainly will not hurt anything. I hope that is all it is.
Keep us posted
Have a good one !

 

Oh, yeah...have I asked you before whether or not you used to own a Land Rover? I seem to remember your alias from my old Land Rover days on another forum.

 

Since your fuel mileage is normal, I think your vacuum lines are good. No warning lights on the instrument cluster, so I'd say all your sensors are good. You could put a can of Seafoam in your fuel tank, and it should get rid of any moisture in the tank, then go straight gasoline, see how she runs then.

No, I havn't owned a Land Rover. I was going to look at one about 20 years ago, but it was a little ( well, a whole lot out of my price range). I have two Jeep Wranglers, one is a Rubicon. Depending on who you talk to, I am blessed or cursed,
Its all good.
Let us know how it goes ,
Have a good one !

 

f60 - If you have a 2018, isn't it under warranty?

Why not have the dealer fix it? It sounds like it is predictable, so you can demonstrate the failure to them.

 

I hear you. That is a possibility, though as I mentioned earlier, I hate doing that since these types of problems seem to elude them. I have spent hundreds if not thousands of dollars in the past having dealers try to diagnose a problem like this only to end up diagnosing the problem myself for nearly nothing but my own time.

Luckily the problem is one that goes away if I am patient wait say 10-15sec of warm-up time vs. the 3-5 sec I give it now. I think Seabiscuit might be on to something with the ethanol. Unfortunately, there are no pure gas/non-ethanol gas stations around me. I am going to try some ethanol fuel additives for now to see if it helps. If not, I'll take it into the dealer.

 

Just two cents,
I typically let my car warm up until RPMs drop to idle. It takes about 60 seconds. This get me to over 100 degrees I try and not drive over 3k rpm until fully warm @ 160 degrees. Operating temp is between 212-221 degrees. I live in Cali very mild climate, so time may vary around the country. I drive a r60 and have had various cold start problems. Id try and get it documented at the dealer, sometimes one problem can cause another with these little machines.

 

I used to do this too, but newer cars supposedly don't require this: from the 2018 owners manual PDF (p.209):
I've been following this procedure since new, and it has been totally fine until recently. Or maybe this is part of the problem? I'll post up as I see what the results are from .

 

Just updating the status on this. I put 2oz of Star Tron Enzyme Fuel Treatment in the almost-empty-tank at the gas pump and filled up the rest with Exxon/Mobil 93 octane.

The cold-morning start up for this morning's commute was amazing...no hesitation/stumble! The engine started right up and I could do as I did before and "DRIVE AWAY WITHOUT DELAY."

Thanks Seabiscuit! I'll keep checking for any hesitation at cold start for a while to see if the additive continues to work. Will report back. So far so good. :-D

 

That's cool ! I'll have to look at that 'Star-Tron' Enzyme treatment. I am glad it was something simple. Glad its back to running normal.

have a good one !

 

Thanks again Seabiscuit!

Just an update on this for anyone that might be remotely interested: I'm on my third tank now with the additive. First tank was with 2 oz per the instructions. That worked great. The 2nd tank I tried using 1 oz and the problem came back. Now on my 3rd tank, I added 2 oz again and filled up again. Problem gone again. It is a bit annoying, but looks like I'll be treating with 2 oz per fill-up if I want to drive away immediately without any stumble/hesitation. I know...first-world problems. Damned ethanol!

 

That shouldn't be happening to be honest. Something is not perfect. Hope you get it sorted.

-=>Raja.

 

Just an FYI as "might" be the solution. Was experiencing the same problem intermittently so didn't think of it when took the 2017 S in today for a differentr problem - and they found 2 other problems. Yesterday experienced warning light " Oil at minimum, add quart." While adding a quart of oil isn't beyond my skill level, knew was only 3000 miles since last oil change, and besides not knowing what brand oil they use (I don't like to cross mix) I also discovered there is no dip stick to crosscheck the message, but an electric readout for oil level. So into the dealer I went...and currently in a loaber as took longer than they anticipated. In their review, there was no oil leak so they are topping it, but also indicated that there was a "drivetrain fault" error message that may well be the cold start stumbling issue. They are currently updating the software as the 'solution' which was taking longer than they anticipated delaying addressing the third issue they found. a deteriorating right engine mount. I had noticed what I considered FWD torque steering issue on hard acceleration, not thinking anything of it so didn't mention it. All being fixed under warranty.

You may want to take it in and describe the issue to them, let them check trouble codes.

 

I'll connect the code scanner I just ordered from ECS to work when it comes in to check for codes. I don't think it will cover all issues, but a lot. Certainly won't find a deteriorating engine mount, but hopefully, if there are any faults I can find I can bring it in to have them covered under warranty.

 

I think they noted that when looking for an oil leak. While I related that not showing up on the garage floor, the service manager noted that the lower air dam will hold/hide a lot of oil preventing it from hitting the floor. The good news it, the air dam was clean so no external oil leaks and the exhaust was not oil coated or smelling for internal leaks. Presume they checked the coolant for leak into there. But they would be down by the air dam where could see the mounts and possible oil coatings if spraying.

 

Replying to an old thread (I know) but I'm deliberately bumping this. I had same issues as OP on my 2018 All4 Cooper S, and brought it to the dealership yesterday. I purchased the car 2 years ago and guess what? It's missing 2 years of software updates, including one that addresses both cold-start stumbling/stalling and hesitation while under way. They are applying the updates as we speak and they also test drove the car after clearing the adaptations after the initial diagnosis and already said the car is much smoother. Miraculously, the car actually misbehaved for them, so they got to see my baby's bad behaviour first hand LOL.

The car has just had regular maintenance at the dealership (oil changes, alignment, etc.) since I bought it so there's really been no reason to hook it up to diagnostics until now.

 

Cars designed for ethanol mixtures don't have problems with running ethanol fuels. People still imagine the ethanol causes a problem, but, that's old history on fuel systems that weren't designed for ethanol. Ethanol is used to boost octane rating, as well as act as an oxygenate, which means that ethanol increases the amount of fuel mixture that burns on each power stroke.

It's more likely that the OP should have the software update done. Just because one or two ounces of an additive a couple of times corresponded to a perception that the problem was addressed, that doesn't make it a fact. Humans are fooled all the time assuming correlation and causation are the same thing, goes right along with confirmation bias to fool us.

 

When my tooth hurts, I go to the dentist. Quick fixes like analgesics deal with the symptoms and not the cause. Like going to the dentist, people seem to have an aversion to going to the dealership when there's an issue. Out come the tonics and the additives and the confirmation bias as you say :-)
It will cost me a bit of money when I pick the car up this Saturday (1 hour of diagnostics + 2 hours of applying software fixes) but they've already called and confirmed to me that the car drives good as new.

 

The car works beautifully. The reprogramming transformed the car and it no longer hesitates while driving it and the cold start stumble has disappeared. They reflashed the ECU and the TCU and applied 3 years of updates and reset the adaptations. Other than an issue where they inadvertently deleted my maps and disabled Apple CarPlay (oops!) and which they put right, everything is so much smoother. They did caution me to use brand name gas (Shell preferred) and to avoid purchasing at my corner gas station as certain additives and detergents are crucial to the engine’s running and long term health.