| Re: Car making a knocking sound. (Newbie) Is it just when you start it? Or is it the whole time the car is running? Is your check engine light on? If so you can buy an ALDL (assembly line diagnostic link) reader from wal-mart for $25, you plug it in under your dash and it gives you a code, and based on that code you can find out what's malfunctioning.
According to my repair manual, there's a few things that could cause a knocking sound.
- Ignition timing
- If it's carbureted then it (the carb) might need adjustment
- Improper spark plugs?
- Faulty emissions system
- Vacuum leak |