i got 2 problems first i have very little heat the engine warms up fine and the temp. gauge goes up about to half but the air is only a little warm i though i have a big air buble in the system but i open the heater core hose to get the air out. the water punp is good the thermostate is good i got the truck about 2 months ago and i had to replace the rad. thats why i though there might have been air in it.it is a 94 v6 5 spd.the other problem just started 2 days ago but i think it is getting worse when i am going up throu the gears at around 2600 rpms the engine starts to miss. it seemed to get better as the engine warmed up more but tonight it did not seem to clear up when it got warm.when i bought it i did a tune up and it ran great i just wanted to ask anyone first before i started to pull plugs and stuff.any help thanks

 

was the radiator clogged? chances are your heater core is clogged and just needs replaced. (or cleaned out)

 

I think your heater core is bad. If the engine is really warming up like it's supposed to, your heater core may be clogged.

 

So the heater control valve is working? The vents opening as they should?
Did the miss go away completely and what parts did your tune up involve?