My 1990 silverado has a bad spark knock when under a load, I changed the timing chain and gears (double roller) put in a new crankshat and new bearings, replaced the knock sensor and put on a new throttle body regulator and it still didn't go away, what else could this be? Thanks in advance.
I had the same problem turned out to be a bad EGR valve.
Gary, I took my EGR valve off and cleaned it with carb cleaner, it seems to be fine, do you think it might still need to be replaced? what year was your truck and what excatly was it doing?
I have had my truck since 1997 and it was just replaced and I don't know if it was replaced before my truck has 90,000 miles on it. It would knock when accelerating up hills and would not stop until I let off the gas. When the EGR was changed it now knocks for about a second or two then stops when knock senor does it's job.
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