Hi, I have a 99 isuzu trooper with 160k miles and it started to sound the same. Marbles in the engine. It happened as i was driving home. There was no loss of power, engine sounds good and strong other then the knocking and the oil is good. My dad and I am going to take it apart to see if we can find what is making the sound. We also cant realy tell if it is fromt he top or bottom part of the engine. If someone has suggestions please let me know! :runaround:

Sounds like you're on the right track. Let us know what you find under the timing covers!

We pulled off the fan and got to the timing belt. We started it up to see if we can hear the noise again but this time the noise was different... Bad different.. Turns out to be a spun rod baring... we are getting a new engine tomorrow. thx for your help.....:banghead:

#1, I'll bet...