If your Isuzu knock sensor isn't in peak condition, your fuel economy could be compromised.  Because gas is so expensive these days, it's more important than ever before to have a top quality knock sensor in your vehicle.  Your knock sensor generates power efficiently by allowing your vehicle to obtain an optimal mixture of timing, fuel and air.  When the power is generated efficiently, your vehicle wastes less gas.  Many problems could arise if you fail to replace a broken knock sensor.  At the very least, a broken knock sensor will rob your engine if its efficiency.  At the most, you could end up putting thousands of dollars back into your vehicle for engine repairs if you neglect to replace the knock sensor.  Your knock sensor must burn fuel quickly before it has a chance to reach the cylinder.  If it's faulty, the fuel could detonate in the cylinder and your engine can be ruined.