Need help with mechanical issues

[Ryanking331]

I have a 2004 Honda Civic Ex and a few weeks ago the check engine light came on, I checked the code and it was p1456. I made sure to tighten my gas cap and it still stays on. It has been idling low at a stop, almost feeling as it will stall but doesn't. Then, when I'm driving, it seems like it has trouble accelerating. Then, just about 3 weeks ago, it overheated. Luckily, I noticed it right away and pulled over. I let it cool down and added water to the radiator. Then, got to the nearest gas station and put in coolant. At that time, I was sitting in standstill traffic. Then, last night(2-3am), I was driving a distance of approximately 5miles, from work to home, it overheated, again. It had just sat at my work for 9 hours. I pulled over and allowed it to cool and checked the coolant level, which it needed some, so I added it and was able now to drive it home. It has been really hot out but why would it overheat, that close together? Also, I dont use my ac, the compressor went out months ago and so, I just used a belt that didnt go around the ac. Any help or suggestions would be great appreciated. If I had the financial ability to take it to a shop and just say, fix it whatever it is, i would but I don't have it like that. I'm willing to do any work, myself, if possible. So, I would appreciate replies that lean more towards DIY repair. Thanks

 

[DugSms]

I know this is a couple of weeks old now, but I think you may have a blown head gasket.
A check you can do is to open the radiator cap when the engine is cold and start the car. If it is pushing air out of the radiator while running then it is almost certainly a bad head gasket.
Our 2002 Civic blew it twice while we had it. The first time I fixed it myself. I took off a day from work and ripped into it. It took me and my father in law about 8 hours to fix it.
The second time, I put some of that head gasket fix stuff in the radiator. It helped but didn't completely fix the problem. Then I sold it not long after that.

 

[Mr.Baker]

I have to concur, unfortunately, it does sound like a head gasket, especially if it overheats right off the bat.
Just for the hell of it, along with the coolant check mentioned above, look at your oil too, it should look a bit milkyand have have some coolant in it if the HG has gone bad.