So about a month ago i started noticing my heater becoming less efficient, the heat started blowing colder and colder and i thought that perhaps i was low on coolant/water and this was the reason i had low heat. maybe my engine was starting to run dry. Since then i've been checking my water levels every week and every week it takes less than 1/4 jug of water to top it off but does take a little each time i check.
next thing is about 2-3 weeks ago i started noticing a speratic bouncing idle upon start up that stops once the vehicle reaches normal operating temperature. after checking the heater this morning after a 30 minute drive engine heat gauge in the dead center between C and H and my heater is blowing warm/cold air it is a bit warm so SOME heat is coming out but VERY minute.
about 4 months ago when getting the vehicle smogged i did have to replace the cat and both o2 censors and i did a full tune up during this time replacing plugs, wires, air filter, oil change, etc. was running perfect until this started happening.
this morning i popped the hood after verifying the air from the heater is still cold and grabbed the hose going to and from the heater core and both of them are hot/warm, not as hot as i would think they should be but both do have some heat.
one more thing is that about 2 months ago my check engine light came on and i pulled the codes... i forgot the exact code number but it was one regarding the EGR... i took the cap off one of the egr pieces and blew some air through the filter/cotton looking piece and put it back in and the light went away and the truck ran good. i havn't pulled the codes since or seen the check engine come back on since.
i've done some searching around the forums and am thinking maybe some air is getting into my cooling system somehow. and if so how? it would make sense if air is getting in because i hear that that would cause the bouncing idle problem as well as it would cause my heater issue of low/no heat as water would be having a problem getting into the heater core... ive noticed people talk about burping the system... how does one go about doing this?? also if anyone has any idea how air could be getting into my cooling system or has any other idea what could be wrong based on my description feel free to post. thanks in advanced