Awesome forum. Already solved my AC issue in like 5min!

Ok...I've had this car for about 3yrs. Bought it used with 50K on it. First 2 years were gold, now I'm having issues left, and right, and up...Also down. Anyway here is the last of them.

Last fall my S40 started rough idling at start-up. If I waited a few min, it would "catch itself" and drive, idle normal. If I didn't wait the red triangle would come on stating: "Try shifting up or slowing down". About a month after that it got cold out, and my heat quit working...So I took it to an import shop, not the dealer. They said it was 1/2 gal low on coolant...That's why the heat didn't work . Also that the check engine light was a misfire in cyl 2. They stated that they could find no leak in the coolant system, but that: "It's prob either a head gasket or a warped head." I asked about replacing the head gasket and they wouldn't even quote me. They said to just get a new engine for it and they would install it.

Soooo I then changed the spark plugs, installed a new ignition coil, and checked the oil. No coolant in the oil, and it worked great for about 2mo after changing the plugs and the coil. No misfires at all, but I was still losing coolant.

Well now it's idling rough only when warmed up, but as soon as I touch the gas pedal it takes off smoothly, with no power loss. And I am still losing coolant. Refilling it about once every two weeks. And yes it still holds pressure. When I remove the cap on the reservoir you can obviously see, and hear the pressure releasing.

Recap because I know that post is all over the place:
Symptoms:
Losing coolant with no visible leak, and still have pressure (20PSI) in system
Misfire in cyl2 only. Before, and after, replacement of plugs and coil
Rough warm idle, but accelerates fine when applying pressure to gas

Any common issues with this besides the head gasket or a warped head? I'm at a loss here, and need to make a decision. Get rid of the car, or fix it.

Any help would be appreciated.

Thanks folks!

 

Any excessive water or steamy vapour in your exhaust?
That would back up the head gasket as the likely cause of the water loss.
Seems like the gasket may only leak across to No.2 cylinder when engine is sufficiently hot and the pressure reaches a higher level.
i.e. water jacket / to cylinder leak.
The misfire would be due to water cooled spark plug.
Head gasket job would be my preference to a replacement engine especially if it's otherwise in good condition. Shop around for quotes and try several non dealership mechanics.

 

Excellent...Thanks for the advice sir. WIll do.

 

Check your spark plug color too. A cylinder burning water/coolant will have a pure white spark plug. It's constantly being steamed cleaned.

 

Yeah I checked for a few months ago when I changed the plugs but couldn't see any noticeable discoloration. Then again when I did that I found out that the car had the wrong plugs in it...They were like 3/8" short.

I put some fuel system cleaner in there...It seems to have helped the rough idling. Still losing coolant to a certain point though. Once the reservoir get down to almost empty, it stops leaking...Weird.