Sounds like an ignition coil packs. A friend of mine had one of his take a crap last summer and it started with symptoms like yours, difficult to start, would take a couple tries or sometimes never start and if it did the ilde was off. It is a $30(single unit) part if you can locate the one that is bad but we simply replaced all 6 of them(one per cylinder) for about $160. It is a pretty simple fix if you are slightly handy and have some common tools.
Here is a link if that turns out to be your problem
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