i have a 94 Z28(auto) with 93,000 miles. The other day wen i started it a quiet ticking noise was coming from my motor and after the car ran fo a minute it went away. the next day the noise came back and now it wont go away and if i rev the car a little the noise gets a little louder and faster. anyone know wat it could be? also the car runs rough at idle an shakes alot.

 

It sounds like an exhaust leak. Try an see if the noise if coming from the valve covers.

 

90% of the time, ticking is caused by an exhaust leak, inproperly adjusted roller rockers, or a loose spark plug. all easy fixes, so check those and see if the noise comes back

 

yea i think it might possibly be an exhaust leak because today before i left i popped my hood and i felt air coming up from behind the alternator. Would that make the car run rough though?

 

yes because there is unmetered exhaust escaping and ticking noise can result in false knock aswell

 

hmm im still unsure. this all started becuase my radiator clugged and the car overheated. now im unsure wat could cause the ticking.. if it is an exhaust leak how could it make the car run poorly to the point where it shakes?

 

uhhhh...might be a headgasket and water is mixing with the oil, check your oil and tell me if it looks milky

 

i checked my oil and it looks fine. and the car isnt blowing out any white smoke. i dont think the headgasket is bad although i am changing it this weekend. what could the ticking noise be?

 

Things to check:

1. Missing or broken exhaust manifold bolts, especially at the rear of the driver side manifold.
2. Blown exhaust manifold gasket. Move your hand around the manifold near the gasket to feel for hot air before the engine gets too hot ;-)
3. Damaged lifter roller or cam lobe - use a mechanics stethoscope or screwdriver and place it on the valve cover over each cylinder and hold it to your ear. If you hear ticking coming from one cylinder, it could be a chip in the surface on the roller lifter or cam lobe. This happened to me twice on the number one cylinder, the first time with about as many miles as you have now. This would not explain the rough idle though.

Hope these help.

 

what would explain the rough idle then?

 

the rough idle would most likely be the exhaust leak, just as 87 bandit noted, because the knock sensor hears the ticking and pulls timing because it thinks your getting detonation.

 

Check your right side motor mount ~ my 94 had a ticking that drove me crazy & it ended up being the right side motor mount ~ look at how its constructed & you will see that when the rubber bushing ages/wears there is a metal tab that will strike the mount & make a ticking sound.

 

The knock sensor doesn't "pull timing" at idle, but a bad enough exhaust leak will pull in fresh outside air during the negative exhaust pulse. This air will be read by your O2 sensor, and the ECU will compensate by sending more fuel.