Grinding or scraping noise upon acceleration

2002 Honda Accord coupe (168000miles) makes a grinding noise when pushing the accelerator especially after the car warms up and when first accelerating. The gas pedal was sticking and a mechanic sprayed it with something to remove the gunk but also put something through the system to remove gunk buildup. I also recently had an oil change. A new transmission was installed in September of 2011. The seal at the top of the oil pan was replaced with the oil change and I was told it has a small oil leak at the bottom and to get it checked at the next oil change.