Took my Saleen out for a stroll and the temp gauge hardly moved off the 130. could it be a bad sending unit or gauge. I was out long enough for the engine to reach operating temps. is the sending unit on the rail coming from the gooseneck area.
The sensor in the hard line is the ECT. That tells the computer what the engine temp is. It has nothing to do with the gauge.
The gauge sending unit is in the drivers front corner of the intake manifold. It has a 1 wire connected to it. The stock temp gauge is known for being flaky. You can check the sending unit. Do a search and you should find something from jrichker or hissin50 that has some good info as to what the resistance of the unit should be at different temps.
Agreed. The stock gauge is fairly useless and they can get a little erratic. A bit of corrosion on the ground-side can keep the reading lower than it would otherwise be. You could try attaching a wire to the sender housing (the sender is just behind the dizzy, as RC noted). Ground the other end of the wire to the neg battery terminal and see if your reading is more accurate.
A new parts store brand sender is all of 4 bucks, so you could throw one of those at it too.
If the upper radiator hose got hard and/or real hot, chances are that the t-stat was opening, which means the gauge read low. A real gauge is a neat way to go.
You could use an IR thermometer to infer temps throughout the system if you desire.