I’ve searched hi and low but can’t seem to find anyone with a problem like this…
I have an ‘08 LR3 with the 4.4 V8 with 110k miles. The car runs GREAT and I love it, but there is JUST ONE problem: each morning it stumbles on its first attempt to start. I attached a video and really hope it works cause it’s worth 1,000 words. But basically when I turn the key the engine can’t seem to make it to the warm-up idle of 1,200 rpm. It sputters and stumbles for 3 seconds or so then either stalls or catches. Tach jumps around from zero to 500 or so rpm.
if it stalls, then my second attempt to start goes flawless and I’m good for the rest of the day.

I tried cleaning the MAF. Cleaned the Throttle body. New air filter. NAPA battery/alternator tested ok.

I’m really lost here. Anyone ever had anything similar?

 

Don't see the video. Try cycling the key on 2 times before you start and see if the stumble still exists. It sounds like to me you have a fuel pressure bleed down when it sits overnight.

Cycling the key should prime the fuel system, and if no more stumble it will be time to start checking the fuel pressure at the rail and looking for culprit for the pressure drop.

 

Problem solved…. Replaced EGR.
Happy Driving!

 

Was the stumble similar to this? Already did most of the same things you tried with no luck.

 

Yes, that is exactly it. Sometimes it stalls, but if it does it starts and runs perfectly after that.
Does yours also ONLY happen after the car has been sitting night?

btw, the egr did NOT solve it. But I have some new ideas.

 

Yes, does it only on the first cold start. Too bad on the EGR. Mine is in the shop for a new alternator but will report back if I figure out a fix. It seemed to maybe get a little better after I added some Techron fuel injector cleaner but then got worse again. I have a can of BG44K ready to try out when I get it back.

 

So I have a lot to say about this, as I’ve been researching for what seems like months.
I believe this problem all started after adding the BG fuel cleaner, because this problem started similar to when it was working it’s way through the tank. But I have no other proof.
My dealer thought along the same lines as you and did a fuel injection cleaning. It’s hard to say if it helped as the car started up fine the following morning, but all mornings after that were problematic.
Now I believe it a sensor which is getting tired. Some threads lead me to believe it’s a crankshaft sensor or coolant temp sensor. I’m really lost on this and am VERY eager to hear about your findings as well.

 

Oh one more thing I forgot to mention. The dealer installed new plugs as I have 60k on mine, but that did solve this issue either.
May I ask why you’re changing the alternator? I wonder if that has something to do with it?

 

Yeah, wouldn't start. Jumped it but you could tell it wasn't getting enough power. Dash lights flickering, park brake fault, and nav screen restarted every time revs climbed above a certain limit. If I really gave it gas the transmission would jump out of gear. Drove it around for an hour like that to see if it would charge the battery and it still wouldn't start up again when I shut it down. Battery and alternator were both just replaced last year. Failed alternator at that time was OEM I believe. Got the same low power and wouldn't start on its own symptoms about a week after smelling a strong electrical burning smell. Thought it was the battery at first back then, replaced that and it worked fine for a week and then it did the same thing again (wouldn't start). Replaced the alternator with a remanufactured Bosch and it was fine for 8 months. So either the Bosch is junk, or something else is going on.

When it does the stumble, it has no issues cranking or catching so I doubt they are related. If anything, my air suspension compressor has been running more often lately and given me the yellow warning light (was just about to replace it) and could have put extra load on the alternator.

Once those two issues are fixed, I'll see if the stumble returns. It seemed to not do it while I was jumping it, but that was far from a normal start up.

Agreed on a sensor as a possible culprit, coolant temp sensor was the first thing I thought of as well (not getting fuel/air ratio right for a cold start thinking the engine was hot). I doubt the BG44k could have caused it but will hold off adding my can for now.

 

Just to keep you in the loop, I tried jumpstarting in the morning, which seemed to yield normal starts, HOWEVER, when I tried starting the car without jumpstarts, it also yielded normal starts.
so either my problem disappeared, or it’s become intermittent. I’ll keep you posted.
Any luck on your side? Did the new alternator fix the bad start?
thank you again.