Its cold outside, and my heat sucks
 

Well, it just got cold here in Michigan again, and I noticed that the heat coming our of my currently stock '90 sucks balls. Turbo is in the works, but its a daily driver in the meantime.

I bought the car in December, drove it home 2400 miles (from LA to Detroit) and then parked it for the winter. I just started driving it a few weeks ago.

The car warms up normally according to the temp gauge, but the air coming out of the HVAC system is tepid at best. I don't think its a thermostat issue 'cause the temp gauge reads fine.

With the blower on full, I notice a significant loss in output from the vents when I change from cold to hot. Seems like the heater core is acting as a significant air restriction. Could this be clogged somehow?

I did some searching (mainly on M.net), but there did not seem to be any answers there. I saw some people with a similar problem and the answer seemed to be to check the fresh air inlet for debris. I will do this, but it seems like a blocked inlet would cause the same restriction for both cold and hot, not only hot. Also, the car has A/C, and it seems like the A/C coils would catch the ---- before getting to the heater core.

Do I have to tear the entire dash apart to get at the heater core to clean it out?

Any ideas? I really don't want to ask the m.net dorks.

You don't want to ask the m.net dorks?

Because the heater core is performance related, right?