Something to keep in mind and many people seem to forget (or choose to ignore). Is say your MAT resistance checks out to within spec., but what is the value at the ECU or PCM plug. When all else fails, you got to get serious about the whole thing and check the resisitance at the ECU plug and clean the contacts at the ECU plug and make sure they aren't loose or backing out of the holder. If the sensor checks out all the way back to the ECU (PCM), you can be fairly confident it's OK.
I've found enough discolored, full of moisture, loose, bent, oil covered, fatigued and broken wires and other various wire and connector calamidies to make me suspisious of all of them.
Checking the sensors is a quick check, checking them all the way back to the engine controller is a thorough check. Be carefull to not cause more damage than you uncover and fix. Speed isn't your friend and force is your enemy.
I got bit in the rear by that not to long ago. I checked my engine temp. sensor and it tested OK, the same as the MAT. One last check and a connector cleaning and things changed noticably. I sure wish I would have cleaned the Engine temp. sensor connector first.
I was noticing the other day, my motor was running a little rough and probably needed a tune up. I hit a pot hole at around 30 MPH and the motor suddenly started running really good. Instant tune up, a contact or ground somewhere, is making better contact now than it did. I've really been contimplating cutting out every connector and ground in the motor, soldering and bypassing all the connectors. And only testing at the ECU.
