my mercedes 1989 260e idles but when i give it gas it sputter and dies replaced the fuel filter and plugs and had the fuel pump checked problem started after i added a fuel adative "seafoam" what could be the problem??????????

I wouldn't think a fuel additive could cause such a problem as it is a very low concentration added to a full tank of gas.
Your problem may just be a coincidence that its only happened since you added seafoam??
Have you checked your dissy cap and rotor??, remove and have a good look at it, look for white/grayish track marks and general arcing evidence, if it is still fitted you will have to remove outer casing from cap (black cover over orange cap), so you can check each lead post. check this first and post back .

my dissy and rotor are brand new with only about 3000 miles on them both and they look fine

I had a problem that sounds the same. When I used kickdown from a standing start, the car would take off rapidly and noisly but at least would go. I had the injectors, plugs and plug leads changed but the problem resurfaced shortly after.
I looked into the block diagram of how the electronic components should work and that indicated a mass airflow sensor (the car doesn't know how much air the car is using and so doesn't give it enough gas, kickdown tells the car that it has an emergency and to ignore a few sensors). I paid 150 Euro for a second hand sensor and after a five minute drive to let the car adjust to the new sensor, the problem was gone.


I had taken the car to MB and other very specialist lunatic engine experts (hence the list of replaced parts), no one found the problem. The kickdown test was necessary to prove it though