I have a 2000 R/T Durango 5.9,it idles very smooth and accelerates strong,at high rpms and under a stain(going up a bridge,etc)it develops a spark knock and seems to lose power.The scan tool sends no codes whatsoever.This truck has been very well maintained and has just over 61k miles on it.I know there is a service bulletin on the intake manifold gaskets leaking.Before I take the top of the engine apart I was wondering if anyone else has had this problem and if it was anything other than the manifold gaskets?

thanks
Bill

 

Sounds like you have some carbon build-up on the pistons. The dealer has some spray cleaner that you can put in the cylinder that will lossen the deposits.

 

wouldnt lower octane gas cause this also? what octane do you use?

 

BadStratRT.

Do you have a part # on the cleaner. I remember reading a bunch of stuff on this over the past few years with the 318/360.

 

I only use 93 octane Amoco gold in it.Anything else and the knocking will drive you crazy.

 

4318001AB-5.75/can

 

I think I found the problem,a cracked pcv hose.I thought I heard a vacuum leak,hopefully that was it.I'm still going to use cleaner though,thanks BadStratRT