94 Sonoma 4.3 z Knock sensor.

[breeze9]

I have a 94 sonoma 4x4 that seems to have a spark knock and has trouble getting up to speed. Checked timing and have done tune up with no change. I was told this has two knock sensors on it but I can seem to only find one and am not sure that this is even it. Where would it/them be located?

[old_master]

Is the check engine light illuminated?

There is one sensor in each cylinder head. There is one wire going to each sensor. When the knock sensors detect spark knock, the ECM retards ignition timing up to a maximum of 20 degrees, or until the knock is no longer detected, whichever is less. When timing is retarded, engine power output is reduced. If there's a problem with the sensor(s), the check engine light will come on and set a code in memory.

Disconnect the Electronic Spark Timing, (EST) connector, tan with black stripe wire behind the carpet, next to the firewall by the passengers feet. Adjust ignition timing according to the decal under the hood. Reconnect the EST and see if it still has spark knock. If so, check the EGR valve operation and the passages for restriction.

[rprough]

I have a 1993 Sonoma with same engine. 1 knock sensor in side of engine block on drivers side below #3 plug and other knock sensor in rear of passanger side cylinder head.