hi, my check engine light will come on instantly upon startup even after i clear all codes. the code is 1-4-3. it's for the front knock sensor. if i hook into the pin for this ,i think it's # a2 at ecm the sensor works great if you hit it lightly and check it with a labscope. but i can't verify the ground. if i ground labscope to the block its fine but if i ground to the pin # a17 i think i can't verify the sensor. i checked the cam timing it's fine and also car shows signs of not having quite the snap it used to have. any help would be appreciated as i'm much better at the rear wheel drive models...thanks to all