97 nissan maxima codes p0100 mass air p0400 egr ? P0325 knock sens whst the cheapest fix for these

Question

Need to know the prices on the parts and/or the cheapest way to replace or fix existing

Answer 1

Visual inspection would be the first to to determine the fix. How the cooling system low coolant level or radiator leak or coolant leak will cause the engine to runner hotter than usual. this can cause P0325 and also the EGR  not operate, If the cooling system is fine, the next would be the P0100, a faulty MAF system will surely make the engine sluggish and also set a P0325 and the EGR to not operate, check the MAF air duct tube for any breaks or tear that leads to the throttle body.