Please help my w124

[300 CE ray]

My 92 mod 300 ce w 124 started to give me trouble today.
It have 143 000 miles total.

At any speed when pedal is depressed and hold steady,everything is normalt, or even when I let go the pedal totaly and the car start to deacclerate.
My problem starts when I let the pedal out just a little bit, etc I overtake a car from behind and just ease out on the pedal and the car start to run rough and hesitate/sputter.When pedal is depressed again it accelerate just fine.
Also on hard take off everything is normal.
Any one out there that know what this could be??
Any reply is highly apprechiated.
Ray

[psfred]

Check ignition (cap, rotor, wires, plugs) and for vacuum leaks -- serious throttle lag is an indication that all the air isn't going through the air flow sensor,

Peter

[300 CE ray]

I changed pluggs today-better for 20 minutes back to trouble.
It kind of sems that it becomes worse the longer I drive

Will buy cap,rotor,wires etc.
How do i check for vacum leaks???
Thanks.
Ray

[psfred]

Inspect the vacuum lines -- they have small rubber connectors on the ends of the hard plastic lines. These rubber bits are usually dead by now, and leak. Also, the idle control valve (under the air filter housing) has two large hoses that get hard and come loose, big vac leak. These must all be replaced if bad.

Be aware that constant over-rich running can be a fuel distributor failure, and this is expensive! If the plugs are black, this is a possibility, although I would not panic until I'd checked out the mixture control system (EHA, oxygen sensor, etc).

Peter