I took my car into the shop due to poor acceleration, the owner said the problem was because of the spacing of the spark plugs, huh?!

I have a 2009 Honda Civic that suddenly began to struggle to accelerate; especially uphill and with the air conditioning on.I took it into a reliable shop and the owner ran a pretty cool test that checked results on what appears to be anything electrical and on the engine. The transmission is perfect.Now, yesterday my mom calls me to say the shop owner found the problem. The previous owner of the car had gotten a tune up done and the spark plugs were put back wrong? Something along the lines of that, but they were spaced back out and the car runs perfectly again!Now, how could have that caused that to bother the acceleration to be problematic? I only understand 30% about vehicles but am trying to learn, so bear with me.Most important question now... How much will the price be? I don't plan to pick up my car until this weekend and I don't want a nasty surprise. My mom says less than $100, but she's not fully positive. Could somebody give an estimate?The owners of the car shop have been friends with my mom for years. So they're very reliable! via /r/cars http://ift.tt/2swSz95