Cold Start shakes, misfires & exhaust sputter. Not just another thread...

[Danger]

Ok, I'm at a loss here. I know there's been quite a few cold start & misfire posts out there. I have gone through quite a few.

During cold starts (in all weather types, but worse in winter), my '01 3.0 shakes and sputters, sometimes getting worst the longer it idles but back to normal after a few restarts. I went to autozone and had codes read; got random misfires and also cylinder-specific misfires with "fuel cut-off.

Now, in the last 3 months I have replaced the CCV and all its hoses + dipstick with the "cold weather" kit, have replaced the valve cover gasket, the secondary air valve, the DISA valve, cleaned the ICV & MAF sensor, replaced the camshaft sensors, and vacuum hose to fuel breather pump. Also about 12 months ago, the plugs and coils were replaced among other (non-related parts). Recently, I checked the coils and seemed ok but still get the rough start. My check engine light went on a day after I cleared the misfire codes and I'm about to lose it.

I have to say that once warmed up, the car runs better than ever, but these morning misfires are killing me. Any thoughts as to what I should check next?

I do have an oil leak from the oil filter housing gasket that have yet to fix, but I wouldn't think this could cause misfires.

[mywidebody02]

How old is your battery. Mine was the original and did the same. It never read over 12 and would die fast if I left the key on for a little bit. Changed the battery and had a few below 30 mornings and so far so good.

[imola38]

Sounds like you've done your homework on this and have replaced just about every related part possible.

The only other possibility that comes to mind, (as long as your SURE you dont have any vacuum leaks) is a leaky fuel injector or two. They tend to leak fuel as the car sits overnight, then on the cold start, the excess fuel in the cylinder(s) causes the rough running until the engine has run long enough to clear itself of the unburned fuel. Unless your able to remove the fuel rail and test the injectors, you may want to have it professionally diagnosed.

I also remember an oddball problem similar to yours a few years back. This was on an E46 but with same M54 engine. Same complaint and after chasing the problem for a while, it ended up being faulty intake lifters that were very slow to pump up when cold, causing rough running. Maybe also perform a cold comp. test and see what you find.

Hope this helps and let us hear back!

-Ben

[Danger]

Originally Posted by mywidebody02

How old is your battery. Mine was the original and did the same. It never read over 12 and would die fast if I left the key on for a little bit. Changed the battery and had a few below 30 mornings and so far so good.

Thanks mywidebody02. That's a good point - my battery is the original as well (2001) and the X's got 156,000 miles on it. But would a low battery cause a misfire or just crank and rough start? Is there a tell tale sign of a weak battery? I will go to Autozone or PepBoys and have the battery tested.

[mywidebody02]

I had misfires on 4,5,8 cylinders. If the battery is weak and in the cold is even weaker then that could cause the misfires. The truck uses slot of juice to get all the modules and lights coilpacks, etc. If it's low and either the spark or fuel injector camsensor,etc is starved it could cause problems. I changed mine and even the lights inside were brighter when I opened the door. If it's the original BMW battery it should be stamped on the negative with the day and year.one was 30/04 Which is the 30 th day of the year 2004. I payed with my bmwcca discount 170 for the 90 amp. Yours might be cheaper.

[Danger]

That makes a lot of sense. Thanks again, I guess with what I heard about the bmw battery being "lifetime" I never thought of it first - I had even cleaned the ignition switch but didn't think to trace back to the source of power. BTW did you try using a battery charger first or went straight for a new one?

[mywidebody02]

After I took it out I left it in the charger for 4 hours and the light always stayed black. Never went back to green. I spoke to the parts guy and he said they are good for 5 or6 years. No such thing as lifetime battery or fluid just depends on what you consider a lifetime.

[c4racer]

you might also want to replace the coolant temp sensor. Probably not related, but cheap to replace and they can cause something like this.

[Danger]

Hey guys. Sorry for the belated update, but figure this could help someone else. After doing all of the above, including replacing with a new battery which was due anyways, I still was getting the codes but isolated to cylinder 4 misfire only. So I went back and decided to take all the plugs out (I did not do this since they had been replaced by the dealer less than 11 months ago). Low and behold, the ceramic part of the plug holding the electrode was cracked! Replaced the old Bosch plugs with NGK Iridiums and no misfires to date. I was lucky that the cracked plug did not break off and cause additional damage to the engine! The old plugs looked so bad that I am wondering if the dealer replaced them at all...

[Stormtrooper]

Not to highjack your thread but I'm having almost identical problems/ symptoms with my 06 X5 4.8is w/ 60,000+/- mi.. Other than dash reading "Check Engine Soon"; Diagnosis Comp. reads: several codes: 0x29CC, 0x29D2, 0x29CE "Multiple Combustion Misfires Cylinder 6xAbove maximum threshold" Says the exactly the same for cyinder 2. Changed the plugs from fact. to "Denzo?" Iridiums. Seamed to work initially but realized it was just because it was restarted that the symptoms would go away just to come back again the next morning in a fresh start.

Dont want to have to replace part by part like Danger had to do until it's right, anyone have some new/ better/ other advise?

Desperately Serious,