She doesn't sound good. 1500 to 2500 in neutral and or drive, it knocks a lot. Hoping it was the purge valve but not a chance. Exhaust leak at the manifold?
Figure if it was rod or such it would make the noise throughout the power band?
All other aspects of truck are great. Idles perfect. Get over 8 around town and 10 highway. Oil is clean. She drinks coolant though but I can smell the heater core leak. It's California so I'm not in a rush to peel back the dash.
Take a listen if u have a chance.
Thanks in advance for the help.
1999 2500 4x4 v10 auto tranny 178k