'88 260e hard to start & dies on idel but runs fine at highway speeds

I have an 88 260e that recently developed the problem of dying when it hits 1000 rpm. It will not start unless you give it some gas pedal, and if you come to a stop sign and brake without keeping your foot on the gas, it dies. Otherwise, cruising down the interstate, it runs fine. I have replaced the fues filter so far, but since there doesn't seem to be a service manual for this car anywhere on earth, I'm not sure where to go from here.

Any help would be appreciated.

Thanks,

Darren