Why is my car struggling to accelerate?

I recently had my oil changed, and ever since then my car has been acting strange. It was kind of "bucking" when i drove it, replaced the spark plugs and that stopped. Now when i drive it it struggles to accelerate. Meaning when im giving it alot of gas im going like 10mph. Check engine light never comes on, and this only happens after ive been driving the car for more than about 20 minutes. When i got the oil changed i know they over filled it, and didnt replace the filter properly. Any idea's on what could be the problem? The car is a 1987 Toyota Camry, 172,00 miles.