'95 Civic coupe.

This morning I started the car after not driving it for almost a week, it was cold out but not freezing.
The car took a bit longer to fire than normal (normally it'll crank over 2-4 times before firing off) but this time it cranked about 5-6 times then sputtered to life momentarily and immediately died.
I turned the key again and it cranked and cranked and cranked till I let off the key (felt like when my ignition coil went bad but that's been replaced less than 3 months ago).
I turned the key again and 5-6 cranks later it started to fire, but it was rough, I had to throttle the gas to keep the engine going.

The weird thing is, once the engine fired off there was a horrible knock/slap noise coming from the engine. Not sure what it was, piston-slap or something. It was MUCH louder than a valve and I thought somehow I had a rod or rod bearing go bad overnight.
Eventually after 10-20 seconds of idling it quieted down and went away.
It's not returned since.

The car was super low on gas and I knew I had to stop at the gas station first thing. While I was there I checked the oil and oil level is good (recent oil change).

So I'm wondering what that could've been?

 

Piston slap, it's normal as they get older.
Mine does it when it's cold out, or if I have started it in a few days.



Put some gass in it, and see if the starting issue continues. My guess is, it was very low on gas.
Mine will do it too if it gets too low.


Also, could be the battery.

 

Well it was REALLY low on gas, which is why I hadn't drove it in a while (my other car had a full tank).

The car runs great normally and ran fine once the slap went away, but it was LOUUUUD! Like I thought the neighbors were going to look outside the window...

 

Put some gas in it, and drive it around for a while.


Sometimes it can be really loud. My car was so loud one day, i really thought I spun a bearing,freaked and shut it off. lol

That time it hadn't been driven in almost a month, and it was winter.