Possible coolant temperature sensor bad

Is the service engine light on? If so, get it scanned. They will do it for free at AutoZone, Advance Auto, and O'Reilly Auto Parts.

With no service engine light, we will have to do a little guesswork. I would start with a new fuel filter if it has not been replaced yet. They usually need to be done around the 100,000 mile mark and when they start clogging up they can cause the hard start that you are talking about.

A clogged PCV valve can create gassy smells, and if it has not been done in a while, then it is a good idea. They usually only cost about $4.00 or $5.00 at the local parts shop.

You should also look for broken vacuum lines. Here is a how-to guide: https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

It also would not be a bad idea to look at your air filter. They should generally be changed every 15,000 to 20,000 miles or so. I take mine out every other oil change and beat the dust out of it and flip it around. Seems to make it last a little longer.

Finally, a dirty MAF sensor can cause all kinds of little running issues, may not trigger a service engine light and code, and is ridiculously easy to clean. Simply buy some MAF sensor cleaner (it is an aerosol) and follow the instructions on the can.

Let us know what you find.