Rough start, runs hot, flickering lightsk

My lovely 2004 158600 mile honda civic has been feeling under the wheather latley and all my fixes don’t seem to well… Fix it. I’ve only owned the car for about 3-4 months. (I was told last week by a third party the car sat for awhile before I got it). I first noticed it liked to start a little rougher than I liked, but never misfired. then a month later the headlights and dash lights began to flicker at a constant rate of bright to dim. Sometimes when I’m idle the lights don’t flicker. Within the last day when I first start it up itll idle a bit rough with a hiccup once or twice and then is fine once I get going. I changed the spark plugs last week but no luck on a fix. The battery is only a year n a half old. I thought maybe the alternator but it’s been a growing issue for months and many miles. Where as im my past experience when the alternator fails its a fairly quick process.

The second problem I have is it getting hot. The first time was at a drive through. I immediately changed the thermostat. Then it happened a few more times, I never let it get hot enough to overheat and turn off, but hot enough I knew I needed to pull over and let it cool for 30 mins. So I changed the thermostat again, radiator, and coolant hoses. That seemed to do the trick though yesterday it got a little hot (maybe just a little past half.) Which wasn’t too awful but hotter than where it likes to sit.20200130_123150|666x500

Anyone have any ideas on where I need to start? I’m wondering if the heat issue has to do with the other issue. Likes its working the engine more. No check lights have gone on btw.

It’s very hard to diagnose a car when you know nothing about its history. I would certainly do all the routine maintenance - oil, oil filter, air filter, condition of coolant, etc.

Overheating during long idles (like at a drive-thru) can be a problematic engine cooling fan not turning on when it should.

For the electrical system, suggest the basic battery/alternator voltage test as a way to start: Before first start of the day the battery should measure about 12.6 volts; immediately after starting the engine, 13.5 to 15. 5 volts. What does your shop measure?

I do like the cooling fan for overheating, but do not trust the time the car has sat unused and think the gas may be spoiled.

She’s been driving it for 3+ months, I think any bad gas has been used up.

Check the voltage at idle. Than you know if alt is good. Is it using any coolant?

Sounds like a timing belt that has slipped a tooth . This could cause it to run rough and even run hot if the timing is off . Dont know what engine you have so dont know if it’s a belt or chain . If its a belt has it ever been changed ? Also make sure the fan is coming on when needed .

Ohhh, that’s a good suggestion. I actually don’t know if it’s ever been changed before. If it is the timing belt I might just change the belt the water pump any alternator all at once. I’ll take it to auto zone this week and check the alt/battery. Thank you all for the great advice.