94 chevy lumina has upper engine knock

I'm willing to bet you have weak upper O2 sensors & there's nothing wrong with your knock sensor. But if you want, the knock sensor is under the lower intake manifold in the back that is located under the upper intake manifold also called the upper plenum. The lower intake manifold is wedged between the 2 heads and is an enormous pain in the azz to get to. You can check the O2 sensors with a scanning tool that will show you the upper sensors in bank 1 & 2 bouncing electrical current from about .5v to 5v several times per second. Anything less show weak sluggish sensors. The resulting lean mixture causes a knock. Change the sensors and the knock goes away and so does the engine light after you reset it. It took me 6 months to find this problem after replacing everything else including the 6mth old O2 sensors fresh from China. Now I have Bosch. PS The lower sensors went 2 weeks later & I was told any more problems it's the fuel regulator. 2001 Frontier 3.3l v6. No problems since, it purrs like a kitten. I'd suggest the Bosch, it's a special design for that 3.3l engine.

The PCV valve is located under the hood, center, upper engine area, top of engine, mounted in passenger side of intake manifold. I hope this helps and good luck.

If it's the 3.1L then it should be on the intake manifold on the drivers side toward to the rear of it. If not then it should be on the upper intake and the firewall right in the middle. Hope this helps! Should look like this ^

crank sensor located in trans bell housing.....near where lower radiator hose connects to engine.knock sensor located on back side of engine block below intake manifold and above oil filter.hope this helped.

very familiar with this. it is down under the intake manifolds in the valley of the engine. it is a single wire connector. you must remove the manifolds to replace this item. parts will run you about $100 and take about 3-6 hours depending on your compentance. parts needed are 1. knock sensor 2. intake(upper and lower plenum gasket)set 3. coolant. make sure you drain your radiator prior to doing this as to not allow a bunch of coolant to drain into the cylinders and cause hydrolocking. if this happens you must remove the spark plugs and rotate the engine to spray out the liquid out of the cylinders then reinstall.

There are two knock sensors on your engine, and they are underneath the intake manifold. You will have to remove the intake to get to the sensors.

Under the intake manifold. Make sure you get the harness for the knock sensors. and clean out all of the rust and junk you're going to find donw in the holes before and after you replace the sensors.

probably it is your water pump

loose connections at coil pack or alternator,fuel not reaching fuel injectors properly,vacuum leak at intake gasket between intake manifold/ plenum and throttle body.

I know that the knock sensor for a 1998 Quest with a 3.0 is located on the passenger side of the engine compartment under the intake manifold. You should be able to find the wiring and connector next to the intake manifold. To access the sensor, you have to remove the upper and lower intake manifold. The sensor is on the block between the heads. Hope this helps.