2001 S500 w/ 109,000 miles. Vehicle has been misfiring for almost 3 years. Vehicle has been at the MB Dealership & 2 other reputable repair facilities. In the repair shop for 5 ENTIRE MONTHS this year.

Vehicle misfires on cylinders 3,4,5,7 - Causing the check engine light 2 come on. Vehicle stalls & completely looses power. Had 2 stop the vehicle & restart for the first 1 year of ownership as no one could figure out the problem. Once the car was restarted it would run fine. The check engine light would remain on then eventually go out. This may occur again the next week or 2 weeks later. Been an ongoing problem. The problem has gotten increasingly worse over the last 15 months. Spent over $3000.00 attempting 2 repair.
Last week they told me it “may” need a fuel pump $900.00. Now they're saying it “may” need a computer which would be $1800.00.

To date the following work has been performed but has not corrected the problem.
All sparkplugs & wires were changed
4 new ignition coils were installed on the misfiring cylinders
New air mass flow meter installed
Ran camera through both catalytic converters & they are functioning properly
Intake exhaust system is functioning properly

I'm completely frustrated with this vehicle. I've spent $5500 n the last 2 months on other problems this year.
01/2011 Struts repaired
02/2011 Control Arms replaced
02/2011 Ignition & Shifter locked up @ the same time.

The truly sad part is that I absolutely love my car. I've owned 2 Intiniti Q45's, Lexus LS400, BMW 740IL & finally I got the S500 that I fell in love with on sight. I love the power. I'm a little speed demon (always safely). However this car is beginning to remind me of a bad relationship. I put my time & energy & $ into this car & all I getting is crap. Is it time 2 walk away?

 

Maybe the ecu is messed up, what arte the codes, just misfires ?

 

P2043 Misfiring (See currently valid STIP) (PO300)
P2046 Misfiring of cylinder 4 (See currently valid STIP) (PO304)
P2049 Misfiring on cylinder 3 (See currently valid STIP) (PO303)
P204A Misfiring on cylinder 7 (see currently valid STIP) (PO307)
P200F-004 G3/4 (Right O2 sensor, before TWC [KAT]) : Open circuit (PO134)
P2045 Misfiring on cylinder 5 (see currently valid STIP) (PO305)

I'm stuck taking this thing back 2 MB Dealership but wondering y because it's been there so many times with no luck. How can it be that they can't figure this out. Changed out coils on misfiring cylinders 3 times, changed mass air flow meter 3 times. No luck.

 

spark, fuel, compression, air....thats all thats necessary.

First...compression and leakdown. you may have a few holes that won't hold compression.

2. Check to see if the plugs are firing...this is easy. Look at the plugs...wet with fuel? oil?

3. Injectors. You can try sending them out to be ultrasonically cleaned.

4. Boroscope the intake and head to see if there is significant build up of carbon.

That should get you started.

 

definitely mention to your advisor/mechanic about what Oliver mentioned above, it seems like theyre finding other unecessary things to repair first before they get to the point.

good luck man and keep us posted, dont let her go!!

 

Your computer might need to be re-programmed or
software upgraded?

Do you hear your fuel pumps sounding up, properly before you start her?

 

fuel pumps do not "go bad" for three years...and they don't go bad for only a few cylinders.

If the car starts and runs, the fuel pump is most likely not the issue.

 

Wish it wasn't the truth, but sometimes it just is. Some Benz's are money pits while some work flawlessly. The early turn of the century Benz's were in the dark ages of Benz quality unfortunately. Thank God things have improved since then and now Benz is back near the top in customer satisfaction.

I hope you get this fixed and no more problems but if she keeps having trouble I say ditch the dud.

Happens with all cars though bro. Heard the same from some people on the Bimmer forums and on down the line. Just Lexus LOTS less of course.