Hi there,
Thanks for reading. Here's my problem, I have a 94 Ls and recently, I've noticed my temp. guage has been acting weird. When I'm idling my guage needle goes to the normal operating temp. mark. As soon as I start driving the guage drops significantly indicating the engine's cool, but it's not.
Also, my heat is affected by this. When the engine idles I have heat, but when I start driving there is'nt any heat. The coolant's levels fine with no leaks. Does anyone have any idea why it's been doing this?

 

The symptoms you've described lead me to think you've got air trapped in your coolant.

The fix is easy... when the motor is dead cold, take off the radiator cap and turn on the engine. Also, set your cabin heater temp to full hot, but leave the cabin fan off.

Let the car warm up while parked until the radiator fans come on.
You'll see some bubbles surface once the thermostat has opened up and the water pump circulates all the coolant in the system.

 

In addition, check your thermostat. Hondas/Acura are notorious for bad thermostat due to dirty coolant. I doubt you'll have a bad temp. sensor, but that shouldn't affect your heat, just your gauge readings.

 

On 94-95 Integras, there is a bleeder bolt where the top radiator hose goes connected to the engine block, you can bleed the system from here. Open up the bleeder bolt, turn on the car when dead cold, and add coolant if neccessary until you get a steady stream of coolant coming out of that bleeder bolt - Then tighten it back up right away.