'90 300e...warms Up - Then Dies
 

My car is starting perfectly when cold but after it warms it starts to miss and then before long stalls...

Any attempt to re-start when warm seems most unwelcome, the engine kicks and bucks as though the odd cyl. fires but most are starved for either fuel or spark. Let it cool off...and it just repeats the thing all over. It has new plugs and the mech who installed them said the cap/rotor/wires were acceptable...but who's to say for certain.

Where would one start to look?

Idle control valve: would it matter if car is warm or not?
OVP?
Fuel relay...ouch! it's integral to the MAS and I dont think you can replace only the relay...

Any help appreciated.

Just a thought, Maybe your coil???
Spark plug gap is incorrect or the spark plug type is not for your car
If your mechanic put platinums, take'em out of there

THX...but the plugs were changed after it started dying...no diff.

Kind of like going to doctor to seek advice, but witholding pertinent information. For instance, care to share your mileage. How about a little maintenance history?

These cars require predictable maintenance as the miles roll on. Between 80 and 120 K things start to go bad.

I would do the following. Find another mechanic who specializes in MB and pay him to properly diagnose the problem.

Throwing parts at a problem is silly and expensive.

Just my approach.

'92 W124 Sportline just turned 242,000 miles, but not without a few thousand in repairs. Some were preventative, others were necessary replacements.
Things like 02 sensor, EHA valve, new wire set, new coil, new temp sensor, new cap and rotor several times. Actually more than a few thousand, but way less car payments on a newer model.

Steve

First check coil to see how hot it is when the engine dies. Then check the wire going to the Ignition Module to see its resistance. It is the crank position sensor.