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.

On 23-Oct-2008, buckyevans (AT) webtv (DOT) net (BIG FISH 2006) wrote:

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?

On 24-Oct-2008, buckyevans (AT) webtv (DOT) net (BIG FISH 2006) wrote:

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.