The mechanic said that a hard shift.. like the one on the hill would have pulled the wires tight due to the short length of the harness. He said lots of mazdas have the problem and it causes the bucking. He said the burning smell might have been some spilt oil from the recent oil change or something else entirely. We shall see when it gets fixed... I'm taking a look at some scrapyards tomorrow finger crossed for under 100 dollar price.