Truck Repair: 2004 Grand Cherokee Spark Knock, grand cherokee laredo, 2004 grand cherokee

Question
Hi Van,
I just bought a 2004 Grand Cherokee laredo with 56,000kms. After a few hundred kilometers I noticed what I would describe as light spark knock once the engine gets to about 1500 RPM. It seems as long as I keep the RPM between 1500 and 2000 the noise remains and is worse when going up a hill.
I just had it in to chrysler and they flashed the computer, took it for a test ride and said everything was ok. The noise is still there however. My full warranty is out in less than 500km.

Are they just trying to gid rid of me until my warranty is up so they don't have to fix it?

Is it normal to have this slight ping sound?

The owners manual says slight spark knock is normal at low speeds. This noise seems to occur as long as I am between 1500 and 2000 rpm. And I suspect it is there all of the time but the noise from the tires and wind covers it up once I get to about 80 km/hr.

Your thoughts would be appreciated.

Regards,
Scott

Answer
Hi Scott,
A 2004?
Gee, if the noise is supposed to be there, maybe they will let you take a new one for a ride so you can hear it.

Maybe get a salesman to let you test drive one before you mention you are comparing them.

A vacuum leak could be the culprit.
Van