geoff walsh please-spark plug proble???

i have a slight misfire in my 94 grand prix(3.4),timing belt is ok,no check engine light is triggered and upon pulling a few plugs thgere was noticable white ash covering a few of the plugs and a few were clean,one even looked like it was hardley used and had some rust deposits at it's base,i take it the plugs are worn or are probally bad and are probally the cause of the misfire,am i on the right track here people????also it is almost impossible to get to the back bank of this engine,this engine has long plug wire guides that are not pulling out properly hitting the frame,i read somewhere that another person (geoff walsh)had suggested moving the engine forward to gain clerance, if you read this Mr. Walsh i would appriciate some help,i notice there is a wishbone stabalizer on the front top of the engine,if i remove this and put the car in neutral,will the engine be free enough to pivot it so i can gain excess to the back and remove the plug guides and plugs easier???also why are some plugs covered with ash and some are not???