Tell me about idle knock?

[texasjack]

My truck has 115k miles,and at idle it sounds like something bad in the lower end. I've seen other posts about (idle knock). Whats the cause and what is the cure? Thanks for the help..

[SCUFFY828]

low fuel pressure or a bad injector can cause a knock , need to do some diag

[ridgerunner98570]

Try running some Power Service injector cleaner thru it first before you spend a lot of money. Put about a gallon to a full tank and let it clean the injectors. Then run it till the tank is down to about 1/4. This should be enough time. Also drain fuel water seperator and change fuel filter. Its better to eliminate the minor causes before you start sticking a lot of money into it, andlet us know if the knock goes away. You can get power service at wal-mart for about 12 bucks.

[texasjack]

Yes, I'll try that first.