AutoNation Chevrolet Mesa

2005 Saturn Ion 2 with 70,000 miles, I found my engine light kept coming on. I took it to my regular mechanic, whom I trust to tell me the truth. He replaced the engine modulator coil & spark plugs ($800 +), I drove about 300 miles & on my way to work at 5am the engine light starts blinking & the car wont move more than 10 mph. My mechanic had it towed & replaced the parts, 3 more times! Once I got less than a mile when the modulator shorted out again. I took it to GM Sup Springs, explained what had happened. Told them it was the wiring harness or computer shorting the mudulator out. 12 days later...I got the car back. They replaced the spark plugs, engine modulator coil & catalilic converter...$1500! When I asked why the modulator kept shorting the service rep kept reading me codes & numbers from the GM book. What a load of bs. Never addressed what keeps shorting it out. Said he didnt know the history of the car, but I've been the only owner & I told him the modulator has shorted out 4 times in a 6 week period. Sadly, later, I Googled Saturn Ignition Modulator Coil...OMG! No one, no dealer, no mechanic has been able to fix this issue. Advice? Sell it before it shorts again, as it will. When I went to pick up the car, they couldnt find the keys! Avoid this place, avoid GM. I'm so completely disgusted with this dealership & GM for not having a recall on such an issue, or even the "nerve" to tell me "it cant be fixed". Never owned a car not made in America, but I'm shopping for something made in asia, & not have to call another tow truck or be late or absent from work again from car issues!