04 idles rough and nearly stalls and overheats

[mattfallout]

i just got this car in august and i keep having problems. it's a 2004 gt1 automatic with 90200miles on it. it hasn'thad a tune up since i bought it, but i've changed the oil every 3000miles

in november i started to notice that the i wasn't getting anything but cold air in the car so i replaced the thermostat. the car wasn't overheating but it did start to right after i was done replacing the tstat and as i was driving the low coolant light came on. i added coolant and the light went away and i had heat.

around mid january i started getting an abs dash light and service vehicle light that lasted a few days but the car was running fine and nothing seemed out of order. then the light went away.

just a few day ago after my wife had been using the car for a few weeks(hers was dead) i got into my car and something felt wrong about how it was driving. i noticed when i came to stops it idled really rough like it was going to stall. after driving it like that for about a half hour i brought it back home let it cool then started it again drove it around the block and the engine got hot nearly red, so i turned on the heat the temp went down and i went back home and checked the fluid everything looked fine as far as levels, no oil in the coolant and no coolant in the oil. i felt the radiator hoses and they were cold and definately had nothing flowing though them. it was suggested to me that i replace the water pump, so i did that nothing changed about any of the problems, then i replaced the thermostat again still no change. i found this forum and started reading peoples similar problems and decided to try bleeding the system of air FINALLY i had made some progress(or so i thought) the car wasn't overheating anymore it stays at a steady 200 once it's up and moving and didn't get any higher. but it's still idling rough in everything except neutral. so i tried to take it for a drive a little further than around the block. Now when i tried to acelerate from a stop the car really struggles at first until it gets moving sometimes shaking the car pretty hard especially if i'm stopped more than just for a moment like at a stop sign. i actually had to start putting the car in neutral at stops then throw it into drive and really step on it to keep it from stalling several times. when it is driving it's not really rough at all but the service engine light flashes instead of staying steady. when i got back home the temp was still reading 200 on the gauge on my dash.

I let it cool down for an hour or two then went outsideto start look at it again. theres no pools of liquid under the car and still no oil in the coolant or coolant in the oil. but the radiator hoses are cold again even after the car has been running and driven for 5-10 minutes. and it's back to blowing out cold air but hasn't overheated again...yet

are all of these problems related? what could be going on here?

i have a very limited warentee on this car so i have to do alot of the repairs myself as well as pay 250 a month for it and it's ending up costing me alot more than i bargained for but i'm running out of ideas. i need help/ideas anything!!!

UPDATE: I started the car this morning and it's now overheating again could this be a blown head gasket?

[3100]

Make sure there is enough coolant, if there is not enough coolant to circulate you will not have enough coolant for heater core and thus not get any heat plus you will overheat your engine. When engine is cold add coolant to the reservoir while squeezing the big hose between thermostat and radiator. Do you see steamy exhaust all the time? if yes it is possible that your head gasket is leaking coolant into cylinder and that is what is fouling your spark plug and crating misfire.

for the rough idle part, the best is to use scanner. Flashing engine light is class A misfire which means it is very serious misfire and do not drive or you can damage your CAT. If you do not have scanner you can try this to isolate cylinder. Start your engine, start disconnecting spark plug wires one by one and when you disconnect one that does not make any change to your engine idle that is the cylinder. Now it can be leaking coolant in that cylinder bad spark plug wire, or bad fouled spark plug or bad injector for that cylinder. So remove the spark plug form the cylinder that you diagnosed as bad. Clean the spark plug, inspect your spark plug wire for cracks or other damage. If all tests ok, swithc your coils for that bad cylinder and repeat step one with disconnecting your sparkplug wires if you get different cylinder now you know it is the coil but if you get the same cylinder it is your injector.. good luck

[xeroinfinity]

Welcome to AF mattfallout !

Does sound like you may still have an air pocket trapped in the system. Especialy if you have no heat then all the sudden you do have it.

And 3100 is right about the misfire, another typical 3.4 problem. With a scan tool it'll show which cylinder has the misfire, clear the code and see how it does.
And when the SES is flashing thier is usualy more then 1 misfire detected.

When your engine runs like that sometimes it'll feel/drive like its blown a gasket, hopefully yours is good.

[manicmechanix]

The check engine light flashing is a misfire code has set? You need to get the code pulled up.

With the cooling problem, I hate to say it but it sounds like you might have a bad headgasket. Are you losing coolant out of the reservior or getting pressure in the coolant?

you need to find out which misfire code you have. Pull the plugs inspect them for coolant contamination and run a compression test and/or pressure test the coolant system. It's due for plugs anyway really. In most areas an auto parts store like autozone can pull the codes and rent you the tools you'll need.