Cadillac: Car sometimes dies when coasting, cadillac seville, lengthy procedure

Question
My car is an 88 Cadillac Seville.  Sometimes the car idles so low that it dies.  This can happen at a stop light, when I'm parking, or even going down a hill.  When I'm accelerating, I seem to have no problem.  My father noticed the ISC pin seemed to have pulled back too far and didn't allow the car to idle fast enough to stay running.  I'm curious if I need to replace the ISC motor?  It's very erratic.  One error code I got was E026.  

Answer
That would be the first thing I would check. There is a LENGTHY procedure for adjusting the ISC motor that I can provide you with.

However, You can just install a new one and if your lucky it may work OK. If NOT, E-mail me at: onlineautohelp@msn.com