USA car or not in N.America at all??????????
which one is it, Sierra is a sub model class not a truck actual.
I will guess C1500????? pickup truck? 2wd./
scan the PCM yet, using any OBD2 scan tool for DTC errors?
it is not bad, 99% are not bad so no need to find it.
why not post a problem and not hunts.
the service manual on the car and google searches ends the hunt.
the knock sensor allows the PCM to tune spark timing to use poor grade fuel. and not allow knock and ping. it does that endlessly.
but if say you heard the engine ping, that is a dead EGR
PING (knock or detonation) is caused by poor fuel and crazy high combustion temps.
The EGR system cures it. (and must be cleaned or fails)
some trucks run spec cams that stop PING>
and some use those and a knock sensor..
it is a microphone ,sensor. and if engine bearings pound load
the KS1 sensor lies., to you. (and the PCM)
example rod knock or piston slap noises.
what truck is it,from USA 1998 list
1998 (sierra is a sub class not an actual truck) see?
Toggle C1500 PICKUP
Toggle C1500 SUBURBAN
Toggle C2500 PICKUP
Toggle C2500 SUBURBAN
Toggle C3500 PICKUP
Toggle FORWARD
Toggle JIMMY
Toggle K1500 PICKUP
Toggle K1500 SUBURBAN
Toggle K2500 PICKUP
Toggle K2500 SUBURBAN
Toggle K3500
Toggle K3500 PICKUP
Toggle P3500
Toggle SAFARI
Toggle SAVANA 1500
Toggle SAVANA 2500
Toggle SAVANA 3500
Toggle SONOMA
Toggle T SERIES TRUCK
Toggle TOPKICK
Toggle YUKON
the knock sensor
looks like OIL sender, or desk knob round.
newer 4.3L has 1 KS1, and KS2 sensors one per bank.
1998 , it is one, sensor, rear left of distributor.
left means (USA drivers left side) perspectives.
first google hit found it.
dead egr , cleaned or replaced seen here
https://www.rockauto.com/en/catalog/gmc,1998,c1500+pickup,4.3l+v6,1304659,exhaust+&+emission,egr+valve,4968
×