So after logging in a few weeks of conversation here on the board, I was beginning to feel pretty auto savvy. Savvy enough to think i could change my own spark plugs. Any of you who remember my first few board questions know that this was a huge step for me. So after i change them, Im crusing along pretty well for my first two or three drives (and swelling with pride). Only now when i drive the car i get a hard lunge and disturbing thud, at roughly 20mph. After that i am smooth sailing into about 80mph. After getting this i now baby it through the 20-30 mph range. It still drops very hard. But yesterday I sped into it to avoid being hit by another car. The transition was very smooth, or pre-plug change normal so for the remainder of my trip I would accelerate through that range. have i changed my plugs incorrecty or is this possibly the result of some other ailment? thanks