94 Olds 3800 No Start When Warm, Miss

I have a 1994 Olds 98 with a 3800 motor (non-supercharged), 153000 miles. I have a check engine light on the gives a "quad module failure code". After running the vehicle for 20 miles or so and making a couple of stops, it gets an intermitant chugging at low speeds and then fails to start. I have checked for spark at the coil packs and there is none. After cooling down, the vehicle will restart. Our mechanic said it was an ignition module, but that was replaced today and it is doing the same thing. My wife has to go to the hospital twice a day for intravenious treatments and it is imperative that the vehicle will start for us. I am afraid that the it will become disabled on one of these 25 mile trips. I would like to take it in and have it fixed, but thats not an option at this time. Thanks for any help. Larry