So I'm getting into tuning my own ECM rather than having Kevin (great guy btw) tune it for me every few months.My engine has recently become very strange, lost 75% (most) of it's power in all rpm ranges yet idles and drives enough that I am still driving it daily. Sputters, surges, can't seem to run smoothly at all no matter what I'm doing, part throttle or wide open.

I believe there may be a sensor causing all this mischief. I'll read that too much engine timing or lack of timing can make your car run like crap just like mine's doing (bad knock sensor). So because my car's running poorly and I'm about to get into data logging/chip burning I want to make sure all my sensors are giving me accurate, reliable information.

Where are these sensor locations?
Which are critical for engine operation?
How do I check for a bad sensor?
Which are likely to go out often?

-CTS Coolant Temp Sensor
-MAF Mass Air Flow Sensor
-MAF Relay
-Knock Sensor
-MAT(IAT) Manifold Air Temperature Sensor
-MAP Manifold Air Pressure Sensor
-TPS Throttle Position Sensor
-IAC Idle Air Control Valve
-VSS Vehicle Speed Sensor

Any help is greatly appreciated!

 

I feel like I would be wasting alot of my time and yours trying to detail the locations of these sensors and their function and even then you would not be armed with the information you need to diagnose your vehicle. Every sensor on your list is critical to engine operation. A few are likely candidates for the cause of your problem. My advice is that you find and purchase a factory(Helms Publishing) manual for your car and study section 6C - 6E carefully. This will help you to familiarize yourself with your vehicles engine control system, its sensors and their functions. I would further advise you to purchase a scan tool, if you dont already have one. Understanding sensor ranges and functions, and watch live sensor data while you drive the vehicle will help you greatly in pinpointing your trouble.