Spark knocks going up hills also temp gage not working

If no hose leaks and engine coolant is fine in radiator. I would say its a faulty thermostat. A malfunctioning thermostat would result in temperature fluctuations throughout the operation of the engine. God-Bless!

Check you did,nt knock the wire off the sender switch.

A flashing check engine light means that your vehicle is having a catalytic converter damaging misfire ! Spark plug problem , coil , ignition module , injector breaking down electrically un a load .
They need to hook up a scope an check it .
Check Engine Light Flashing Misfire Diagnosis by Autolite Spark Plugs
Honda , ford , gm there all the same

The knock sensor code does not always mean the sensor is faulty.
The sensor picks up noise and vibration in the engine such as a spark knock would generate, and the computer slows down the spark timing to fix it. If the noise or vibration continues, the code is set.
Could be a noisy valve, or a problem with the crankshaft or other component.

If you have a spark knock on acceleration your timing could be over advanced or you can be at a too high operating temperature.First check the timing, with the vehicle in operating temperature place the transmission in park or nuetral with the parking brake engage Engine turned off..Remove the vacuum hose on the distributor and plug it.Connect the timing light.Disconnect the single wire near the distributor.Start the engine and bring it in operating temperature.Check the timing.Your timing should be at 10 degrees before top dead center

Now the temperature gauge is non op you need to make sure you are at operating temperature and not over heating. After a quick test drive turn off the engine and feel the radiator is there any cold spots that is causing the vehicle to overheat. You could have a plugged radiator.

It detects spark knock, usually caused by preignition, and sends a signal to the pcm, so it can ****** ignition timing,so that the spark event occurs a little later, getting rid of the knock, or ping. This usually happens because we run engines on the ragged edge of what is prudent for timing advance, to optimize both power and economy, and when a sudden load is put on the engine, such as passing or going up a steep hill, the timing needs to be backed off to keep the engine from having spark knock.

Sounds like a bad coil pack. If memory serves they had the double coil pack on the back of the motor that were notorious for going bad and were seriosuly cheap to replace.

I'd also be looking towards a CKP (Crank Position Sensor) in that car.

It possible that you have heavy carbon buildup in the combustion chamber ( causing spark knock)and on intake valves (cause a lean condition).

Is this a manual trans in this truck, if so, try shifting down a gear. But yes a timing belt could cause this, but usually they wont run very well if the timing belt is that bad worn.

have you changed the knock sensor?