1995 Mercury Sable engine dies

My car recently died while driving, and would not restsrt, I replaced the module, , then sent it to a shop to see if they cvould find the problem, after having some other work done to it and getting it running they now find it is trying to die again when they hit a bump, especially when they hit a bump on the right hand (passenger) side. They are trying to find the problem, checking the ground straps and not seeming to find a reason. I can not afford to pay anymore money at this and already have a issue with the work thats been done, so any advice will be welcome.