knocking

you need to go to gas station and use higer grade of fuel, try the top grade of octane 97 ...it will help to solve the sound of knock (knock and ping) to see if it is successful...If not then you need to take it to garage and explain the situation...good luck

Dave Irving you are stupid. don't give advice on a topic you don't know about. to answer the question: what you hearing is called lifter tick. it's due to how the lifters were designed--not very well. check your oil, make you're you are using 5w30 and that it is full. normally the problem is that the car has less oil than at the full level. if you are even a 1/2 quart under full than lifter tick is likely to happen when you first start the car. once the car starts to warm up the oil flows better which get rid of the ticking.

try using a 0w30 wieght oil because its a thinner oil at low temps its gonna fill and lubricate the lifters quicker and therefore remove the lifter tick, its a little more expensive but worth it in the long run

its your cat converter my 98 does the same thing get under it with a hammer an tap on it if it rattles its that .Mine drives me crazy it can cause lots of problems if it starts to fall apart .It will cause it to over heat no power check engine light to go on many annoying things but im 100 % positive its that. Good luck

I have the exact same car, and these models all seem to all develope the knocking eventualy. No big deal really. To fix it i took off the valve cover, tightened a few bolts and tightened a few bolts, and the problem was gone. Only thing you need to get is a gasket to replace the old one as long as you have basic tools.