Skip the auto shop - Our mechanics make house calls

Q: Knock Sensor issue

asked by on

I just bought a 2003 Chevy Silverado 1500 z71 4x4, 135,000 miles, 4.8L V8 with some rust, it does have a slight ruff idle and sounds like lifter knock when hot or cold, if i blip the throttle the knock go's away for a few mins, i changed the oil and spark plugs as soon as i got it home, the check engine light was on as well. i went to advanced auto and had them scan the code, it came up as knock sensor bank 2, i purchase 2 new knock sensors, wiring harness and intake gasket, installed everything and the code came back after a few days of driving it as bank 1 now, i traced the wires from the knock sensor harness and everything looks fine, i pulled them back out and replace them once again. but same thing, engine light came back after a few days. would replacing injectors or coil packs help me any?

My car has 135000 miles.
My car has an automatic transmission.

A: The sensors are doing their job and telling...

The sensors are doing their job and telling you there is a knock in the engine. Even though it may seem like the sound went away, you may not be able to hear it when you drive but the sensors can. The knock sensors are designed to produce a voltage when they hear a knock noise from the engine internal parts.

You need to have the noise you hear checked by a mechanic to see what is the cause and what needs to be done in order to fix it.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Transmission shifted very hard one night and has not done it again

Check the level of the transmission fluid. If the fluid and filter have never been changed that would be wise to do as preventive maintenance. Transmission fluid filters can get plugged and clean fluid will promote efficient and long lived...

Q: Master cylinder missing a wire

Hello. The brake light can come on for a number of reasons. If the brake pedal feels fine, then the problem is usually electrical. If the only light that is on is the brake light it is typically caused by...

Q: Won't start, security light came on - 2003 Pontiac Grand Am

It is possible that the thief system was damaged or memory cleared during the changing of the battery and alternator. You will need to try any other key you may have and if it still is inoperative then will need...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...