Motor Knocking

Ok, I have a 96 Ford Contour GL, It's got that 2.0 Zetec motor with a 129,000 mile's on it. I've noticed when im pulling hill's the motor knocks some what. I've been told it's a loose vaccum hose but I'm not sure, Any help?

if the motor is knocking its generally a sign of a spun main or rod bearing.

Ok, I was being told it wasnt that because it doesnt knock all the time. Also relized when i keep octane booster in it , it doesnt knock at all. So im kinda stumped.

are you sure your not mistaking a ping for a knock?

Yeah I must be, It's like a pinging, no actually knocking. the car doesnt loose any power or nothing. and it only does it during pulling hill's

it may be a lifter is getting cloged and that is why it knocks up hills, due to the lifter not getting alot of oil.

I'm wondering if you have had any luck with your 2.0. I've recently been asked to work on a 96 with the Zetec engine and am having sort of the same dilema. The computer is putting up a 171 code for fuel system lean condition and after driving it have noticed the same symptoms as you. I was thinking if this is running lean it should also be running hot which would create a pinging sound as if the timing was to far advanced. As you are probably aware the timing isn't adjustable so the octane boost is the next best remedy. I was hoping maybe you were experiencing the trouble light also and maybe by now had found a fix. I have searched all over the engine for vacuum leaks but no luck. This one also experiences a bad hesitation when cold and gradually gets somewhat better as it warms up which kinda verifies the lean condition. Don't you just love the new vehicles with no adjustments. Thanks for any input you might have.