Intermittent misfire . . . slow coolant loss

[donutman]

I have a "never there when you need it" problem - "never there" because it never shows when my mechanic has the jeep - 2012 Liberty - usually idles at 550 or so, on warm engine when sitting for a while idle sometimes but not always climbs to ~800 and it idles rough . . . let it sit long enough the MIL light goes on . . . and a few days later the light goes off . . . always showing a misfire on cyl. 5. Over 5,000 miles I have added about a 1/2 gallon of coolant . . . no visible leaks beneath the car. No overheating.

 

[John P.]

Hi, how many miles are on your Liberty? I’d swap the coil on that cylinder with one that hasn’t shown a misfire and see if the misfire moves to that cylinder. Could be a wire since there’s only three coil packs, so carefully move the wire with it. I’d almost call that a serious coolant loss issue if you cannot find any leaks. Could be going inside the Jeep from the heater core, a start stop leak from the water pump starting to go bad, or a worse case a bad head/head gasket. Hopefully it’s just a bad wire causing the miss, and a leak you haven’t noticed for the coolant loss. I’d take a mirror and check the weep hole for the water pump and see if there’s any coolant residue around it.

 

[donutman]

Yeah, bad head or gasket is what I fear - it's a reman engine w/6K on it - first reman had a bad head gasket, company replaced it under warranty after three months . . . other symptoms that i do not know whether they are related or not - sometimes gurgling sound at start up from driver's side