'90 DeVille Stalling Issues

[barbquebutt]

This problem arose over a year ago, went away for about 6 months, then just started again yesterday.

The car will not turn over unless I give it gas while I'm turning the key(yes, risking flooding). Also, it will not idle without stalling. I have to keep my foot slightly on the gas at all times. On the freeway or open road this is not a problem, but as soon as I hit a red light and try to ease off the accelerator, it will stall. From there I have to pop it into neutral and restart it.

MY assumptions are leaning towards something wrong with the vaccum lines, but the cadillac serviceman told me over the phone that it could be an endless number of things. Which might be true, but I'd like to narrow it downif I can.

Anyone have any ideas?

[DFBonnett]

First guess would be that the ISC motor has failed.

[caddydaddy]

I agree, I'd check the ISC motor as well.