Gentlemen, I am requesting your assistance with a situation that has arisen with my 2001 E430.
We have trouble stariting in the mornings and after lengthy periods of rest.
It takes multiple attempts until it turns over, the battery is not wearing down, nor does it appear to be the starter, it continues to crank well, just not turn over immediately.
After the second or third attempt in catches and runs, but will sputter for a bit.
Just recently it sputtered and surged at a stop.
Other then these symptoms, it has been running well.
I did have the codes read when the CEL came on and the reading was a air mass sensor, but we had just replaced the unit within the last 6 months.
I am wondering if this is a fuel pump relay switch or some other control unit.
Your expertise is respected and requested to help me remedy this problem.
Thank you for your assistance.
Steve Dale
2001 E430 125,000
1996 C280 212,000

I also need to inform you that the crank position sensor was replaced in the last 6 months.
We have found that once it starts it runs great during the day or night. It starts well while out and about, but when left sitting for a lengthy period, overnight or a work day, it has this issue.
Thank you for your assistance.

Have you replaced the spark plugs yet?

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Random thoughts...

When you replaced the MAF, where did you buy it? Did you buy just the insert (held in by two screws) or the entire assembly? If the latter, where did you buy it and what brand?

In addition to plugs, have you changed the fuel filter? If so that takes care of the FPR.

One day when you don't need the car for a couple of hours (and it's been sitting all night) go out and start it up. As soon as it starts and is sputtering etc. shut it off. Then remove one plug from each cylinder and see if any show signs of misfiring (black sooty carbon deposits, wet with fuel, etc.) If you find any like that, replace the Fuel Injector on that cylinder.