Have changed the computer, plugs and wires, crank sensor, cam sensor, ignition mod., purge valve. None of this has fixed the problem. Just driving down the road the engine shuts off. I drive mostly on the right lane so I can pull over when this happens. So far I have avoided being hit. The Buick only has 85,458 miles on it.it is a 2004 Buick LeSabre I need help I'm a senior on a limited income and I'm broke need help now and hope this is a recall

4 or more proposed solutions from various mechanics. Buick dealer finally found it after I ranted and raved that they are the experts. Told them to call Detroit if they had to. They told me the catalytic converter had collapsed, causing backpressure in the engine. They figured out by disconnecting the manifold from the engine. Once they did that, the engine started immediately.