rpm dropping @ stop signs&lights.tried everything & it's doing the same thing

Hello, first - Firestone is not equipped to diagnose this concern, unless you run into that one technician somewhere that knows how to properly diagnose an OBD-I vehicle like yours. Second - you do not have a "computer issue". Engine performance with bucking and surging as well as idle roughness and low idle at a stop is indicative of an engine performance issue, with either ignition spark, fuel delivery, air intake or emissions controls issues -- or some combination of any of those. It's also possible you have an engine timing or compression issue. Your vehicle is 27 years old. It's not unexpected to have problems develop over time, wear and tear. No need to jump to the "computer" solution. I'd lean towards EGR issues to start with -- clogged passages and an EGR valve that sticks. But there's testing required there. Beyond that, there is likely an ignition related concern, such as spark plug wires that are arcing under load. It's all guessing! Because I don't have the car here to look at and evaluate. A good shop near you can help you. It's worth the money to get a professional assessment. Here are some shops near you to consult - fill out this page: www.repairpal.com/repair-shops