I have a 90 Integra RS, and when it's warming up it comes up to proper temp. But soon after I start to drive the temp drops all the way cold. You can say come winter it's not very warm inside unless i'm sitting still
What could be the issue here?

 

hey man, i got a 90 RS, it might be that your gettin tooo much air flow, whenever i go faster with the heat up, i get a blast of warm air (feels nice when cold out) but check to see if something is missing in the fromt lip.

 

your thermostat is stuck open...i had the same problem when i installed my fluidyne. would warm up to normal at idle, then drop all the way back down when i started driving. simple and inexpensive fix.

 

While your at buying one. Get a colder running thermostat