Engine idling rough

Yeah I haven't done a block chemical test, and there isn't a radiator cap just a resevoir with a cap and it seems fine. And that's what I was thinking about the sealers too, I was thinking of doing that as a absolute last resort if it got too bad to drive but so far all this time it's been driving the same except it doesn't smooth out at all anymore. I noticed it drives rough at low rpms and once up to speed and at 2000 rpms or more it's not as shakey, Im unable to use the over drive because it runs even worse, I didn't think nothing of it because it builds more pressure and stability at higher rpms which could make it run better, I just don't believe it's a head gasket because last time I had one go out it got progressively worse on que, this thing doesn't, and I've drove it quite a bit. But I could be wrong, my gut just tells me its not.

It's because it's a very pricey part I'd have to replace and if I'm wrong and it turns out that the head gasket is bad I didn't want to throw all that money away if it's going to leak anyway, I thought if the new wires fixes the idling issue then then I'm right and it's the combination of the two, and if it don't then I only threw away $30 compared to $120 for a new housing. If it is a bad gasket then I'm just going to replace the motor since it has over 230000 miles now. I that makes sense.

I ment to say "I hope" that makes sense.

New ignition wires are on and not even a little difference. So if the first mechanic I took it to is right and it's leaking coolant into the cylinder would there be any indication on the spark plug I could look for? And if so when would be the best time to check it? Thanks.

By the way, what was that chemical test you mentioned before that changes color? Is it something I can get at a parts store? Thanks.

I may try the autozone chem test if not real expensive first, cylinder 1 is the cylinder indicated by the trouble code to have the problem and is the absolute hardest cylinder to get to (figures right?), So I will try to get ahold of a super bright flash light and see what I can see, but my hopes of fixing this are starting to diminish. One mechanic mentioned something about an idle air motor going bad as a possibility but for now I'm going to look for a head gasket problem. Guess I'll tinker with it some more tomorrow. The coolant leak doesn't worry me a lot because I can easily stay on top of it but the rough idling is whats killing me since I can't use the overdrive, it goes through a half tank of gas in almost two days, anyway I'll let you know what I find out, and again thanks for all your help!