88 560sl quits when driving
 

My '88 560sl quits unexpectedly while driving down the road. It just stops running all of a sudden. You can put the car in neutral and restart it immediately but this occurrance has become more frequent and is driving me crazy. I've checked wiring harnesses and things I can easily get to. Anyone have this happen to them or any ideas for things to check to eliminate this problem? I want to try and solve it myself as I know how expensive an electrical problem can be when brought to a dealer.

Monitor the fuel pressure during the event.

fuel pressure
 

Novice question-- how do you do that safely while you are driving? Could the fuel pump and or fuel relay be the cause? I have an 84 380sl and proactively changed my fuel pump to avoid getting stuck because I know they go bad around this age and can leave you stuck somewhere. Also changed the filter. New fuel pump is quieter and audibly smoother.

Could be an ignition cause for this proble. But for a fuel system first guess--Question to the owner-- was/is the fuel pump making louder noises? this is the sound of a failing fuel pump. The pump is located around the rear passenger side wheel well. A quiet buzzing noise is ok. A loud buzzing noise means the pump is going. Sometimes if it is bad it will get much louder while drivingA new pump is not too bad-- I think they cost about $250 and did it myself-- relatively easy job but can be dangerous with all the gas, maybe best to give it to a mechanic. I think I posted a writeup here on that see my previous posts.

As an aside, I saw a car that was burned to the ground when they drove off with fuel gauges still connected while driving, maybe there was some other circumstance.

I am also interested to know how this monitoring can be done safely.