Nissan Repair: Ignition timing, 1996 Nissan 4 cyl, throttle position sensor, poor gas mileage

Question
I am unable to get the timing lower than about 15 deg BTDC, because the slot on the distributor runs out of play and it hits the bolt and can go no further.  I have tried it both with the throttle position sensor connected, and disconnected.  It's been warm each time I tried it.  Sticker on hood says it's supposed to be at 10 deg.  Currently getting poor gas mileage and spark plug knock on acceleration.

Answer
Hi Alan -

Have you replaced your timing belt recently? Looks like you are one notch off on the belt.
You will need to go through the motions as if you were to replace the timing belt and re-align the pulleys, camshaft, damper, and carefully replace the belt properly.

Alternately, is the base of your distributor slotted or geared? If it is the latter, then you can simply move the distributor gear ahead one notch, but don't forget to mark the rotor direction before hand as a reference.

Hope this helps -
aloha
Calvin