1998 Gmc safari 4WD knocking noise from engine

• Chevrolet C/K( k= 4wd) pickups.
• Chevrolet Silverado?
• Chevrolet Suburban(no)

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

Sounds like a rod bearing knock.

Bang on the catalytic converter being careful not to get burnt and see if it's loose causing a rattle. Until you determind what the problem is don't drive the vehicle. The other possibility is that you may need an engine. If what you're hearing us a connecting rid knock.

Several possibilities for the cause of your knock. Knock at idle can indicate low oil level. Knock on acceleration can be ignition timing or low octane gas. It is almost impossible to diagnose this without more information.

sorry to say knocking usually a rod knock--wrist pin-bearings-which means removing engine-also the engine cradle and front end dont let u drop the oil pan to get to the lower end of the crank shaft

ok the lifters are making noise, make sure you are using the right oil for your temp zone. also add some lucas oil to your engine oil, it will quiet down the engine.

sounds like an engine bearing has bit the dust,

Hello, I see you have a trailblaber with a knocking noise. It sounds like you have an electric fan clutch issue. Believe it or not your vehicle has an electric fan clutch. It looks just like the older non-electric but if you look on the driver side of the fan shroud that is the wire connector you see. It is an exspensive part just for the clutch but thats exactly what you are describing. It doesn't get louder just fast with rpms. Please rate my answer, Thank you

Sounds like a connecting rod bearing problem. I would have a pro. listen to it.

hi is it miss-firing as it sounds like a knocking noise can be anything but if you can feel it on the accelerater pedal then the noise sounds like its on the inlet valve side which would transfere the noise up the throttle body where the accelerater is located it could be something as simple as a tappet come loose to a burned valve you need to have a look do a compression test and take the rocker cover off see if theres anything come loose yates210456