Fixed Missing, but MPG is in the dumps!

Vehicle: 2011 Toyota Camry Hybrid. 129,000 miles.

I do all the maintenance on it. Use Mobil1. Replaced spark plugs at 103,342 miles. I have Techstream software on a laptop with the OBD usb connector.

PROBLEM:

At about 125K miles, engine started running a little rougher when cold. at 126K I got a check engine light, and noticed also a mild decrease in MPG as reported on the dash. 

Running techstream, it indicated cyl 1 and 3 misfire, and also an "all" cylinder misfire. As I had replaced the plugs, I opted to replace the ignition coils. Bought a full set of 4 at Autozone and installed them. I also ran a bottle of Techron in a half tank.

Engine ran much better, gas mileage seemed to be back to normal (about 32 to 33 mpg), and I passed the smog check no problem.

HOWEVER, now my MPG is way down to 24 mpg (!!!) I think I may smell gas occasionally, not sure. I did have some rough running, including one little bit of severe roughness that was matched with a new check engine light, and a cylinder 3 misfire.

I cleared that code a few hundred miles ago, and the check engine light has not come back, but my MPG is still very low.

Things I am wondering:

• I bought Denso plugs - could they have been counterfeit, and are now failing?
• Is one of the new coils failing?
• Do I have an injector problem?
• Is there something else I should consider?

Any comments or thoughts are appreciated.