Starting Problem- Weird

[97XJ, 4.0, 231J, AW-4, 241K miles, 99+intake, Banks Torque Tube header.]

Usually my XJ starts right up.
Occasionally I turn the key like normal and it doesn't start.

Pressing the gas pedal and pumping the pedal makes it start.

INTERESTINGLY, when I do this I notice that my engine temperature gauge reads "dead cold" and this is usually when it should be reading around 200°.

This has happened a half dozen times, so there is a definate correlation with the engine not starting, giving it gas, and the temp gauge not registering.

I have no idea what this could be.

Any ideas ?

Thanks,
Jeff-97XJ

Usually when the wifes 96 deosn't start right up and I have to work the pedal some to get it going, the IAC is sticking.
I pull the air box off of the TB and squirt some penetrating oil into the IAC open with the motor running, while working the throttle by hand a little. Repeat a few days later. Usually lasts for half a year before it acts up again.

I haven't got a clue about the temp. gauge though.

I have noticed the IAC has a tendancy to stick more when the motor is cold (on the wifes 96). And seems to work better (stick less) when the motor is hot. On my 88 Renix it's just the opposite, the IAC gets sticky when it's hot on occasion.