E500 hesitation as if out of fuel.
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Newbie
Joined: May 2021
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‘05 E500 4matic
E500 hesitation as if out of fuel.
My ‘05 e500 has developed a hesitation that I can most associate with running out of fuel. I wil usually do it once soon after start up and studfers badly.
Once it gets it out of its system the car runs great.
It started about a week ago after having the water pump replaced. Initially it was just off idle and only occurred when the engine was cold and sometimes would lead to stalling. I cleaned the MAF and throttle body and the car team better than it had on a really long time, crisp throttle response and noticeably more power in the midrange.
Monday morning rolled around and it started as usual, then a very rough idle followed by a stall. Cranked right up and ran smooth. pulled out into the road and at about 1800rpm it starts bucking like crazy. Car settles down and ran fine for the 14mi trip to work. Now it does it every time I start it cold or warm. Only once though.
I was getting some low voltage codes from o2 sensors and the big battery is at least 5yrs old so replaced it this morning. It ran great for about 2 hours of errands and then it started again.
Any suggestions on where to look next would be great.
Once it gets it out of its system the car runs great.
It started about a week ago after having the water pump replaced. Initially it was just off idle and only occurred when the engine was cold and sometimes would lead to stalling. I cleaned the MAF and throttle body and the car team better than it had on a really long time, crisp throttle response and noticeably more power in the midrange.
Monday morning rolled around and it started as usual, then a very rough idle followed by a stall. Cranked right up and ran smooth. pulled out into the road and at about 1800rpm it starts bucking like crazy. Car settles down and ran fine for the 14mi trip to work. Now it does it every time I start it cold or warm. Only once though.
I was getting some low voltage codes from o2 sensors and the big battery is at least 5yrs old so replaced it this morning. It ran great for about 2 hours of errands and then it started again.
Any suggestions on where to look next would be great.
Super Member
Joined: Aug 2004
Posts: 545
Likes: 87
From: Southern California
I would suggest looking back at the engine and doing a very close visual inspection. Maybe something was missed during the water pump install? Vacuum leak somewhere? Not likely unless there is a hole in your engine cover, or the MAF elbow was not put back into position properly. That might be as it is not easy to reach and the gasket can get hard.
Also, when was the last time you replaced the cps sensor? Those are known to go bad and can cause issues. You can find a replacement part at most local autoparts store. Might be worth trying it as the part is cheap and you can probably return it if nothing changes.
Also, when was the last time you replaced the cps sensor? Those are known to go bad and can cause issues. You can find a replacement part at most local autoparts store. Might be worth trying it as the part is cheap and you can probably return it if nothing changes.
Junior Member
Joined: Aug 2020
Posts: 32
Likes: 2
W211sedan E500 4matic
Do you have a check engine light? When my 2004 e500 hesitated like that I had a bad ignition coil + some worn spark plugs. I replaced the one bad coil, all spark plugs + all wires. I did have a check engine light and showed misfire on the bad coil.
best.
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