I've been to garages 3 or 4 times at around $300 a pop and they replace a diff. part and say that should do it, and it never does it. We never know when it's gonna start, there's no one set of criteria that determines when it will or won't. ie., rain, heat, cold, etc. I just tried the ignition off-on, off-on code thing to see if that would tell me anything and nothing would blink out the codes. Gettin real close to the gas soaked, lit rag in the gas tank solution.