Rough idle and acceleration

Rough idle only happens when I fill up my gas tank. It will last for a short period of time but once I turn off and restart again it runs fine until I fill up again. Also notice when this happens it struggles to get my speed up acts as if I'm running out of gas.

My car started exhibiting a problem about fifteen minutes of running so it had plenty of time to warm up to normal running temperature. It started when I had accelerated from a stop. I noticed that the power was reduced but it wasn't sputtering. It seemed though to confuse the transmission, it was hesitating between gears. When I had to stop at a traffic signal it felt as though the car was going to stall but did not. It drove fine, no sputtering or hesitating although it was shifting through the gears with a lag. When I pulled into my driveway and put it in park, the idle was improved although the engine had a slight shake. Restarting it didn't change the symptoms. I changed the plugs but no change. I pulled the coil packs and ohm'ed them and both read the same. I know the coil packs can read good but have a problem when voltage is applied. I am retired and on a limited budget so I do not want to throw money at it. It appears to me to be something in the electrical system, is there a way to check voltage to the coil packs and back track from there? Or has anyone had a similar problem that might lead me to a fix?

Why is my kia optima 2002 idle very rough after washing my engine out