Car Stall problems of the 2004 Ford Windstar

Purchased the car used on 5/26/12, drove away from the dealership and the abs warning light and the break warning lights both came on, indicating issues with abs. Took it to the repair shop and was told that the abs module (??) was causing the issues. Car dealership and warranty company refused to cover it because it's an optional system. There appears to have been a recall for this but for some reason my car wasn't included - it was originally purchased in canada, so I'm not sure if that effects recall information. On 6/12/12 driving in to work the car suddenly lost speed while trying to accelerate on the highway. I was attempting to make it across 4 lanes and the car suddenly wouldn't go over 30mph - thankful there wasn't a lot of traffic but this could have caused an accident. Issues continue - car bucks and hesitates when trying to accelerate, there's often a loud pop (backfire?) from the engine when applying the gas pedal. Mechanic replaced seals and spark plugs in engine but we were told that the pcm (ecm?) was causing an electrical issue. Additional symptoms include reduced gas mileage, feeling like it's going to stall or move while at a stop (bucking like it's going to move forward even though brakes are applied) and reduced functioning in the a/c unit.