Nissan Repair: 97 altima stalls, rattles, air control valve, volt ohm meter

Question
I have an ongoing problem with my 97 Altima SE.  180k miles, manual trans.  It stalls when revs go down, like when putting the clutch in while stopping or slowing or at idle.  Getting codes for the knock sensor and TPS.  I've had the plugs, wires and distributor changed, fuel filter replaced, and replaced the harness to the TPS as it was believed it was loose and causing the problem.  It also rattles/clicks when it turns over when starting but only then.  Is the TPS the issue and is this hard to replace?

Answer
Sam,

The knock sensor needs to be replaced since that puts the car in limp mode.  You get bad mileage since the computer retards the timing to keep from hurting the engine.  Basically, if the engine knocks it could damage the rod bearings.  So change that knock sensor soon.  The throttle position switch since that lets the computer know where the throttle is.  At idle it has a specific reading that activates the idle air control valve.  It is pretty much a plug and play with minimal adjustment.  Get a Haynes Manual for the setting process.  You will need a volt/ohm meter to set it.  Cost is $20 for the book and another $20 for the meter.  I would also clean the throttle body to make sure the idle air control valve is free to allow air to bypass and provide it for the idle.