So I own a 2003 Volvo S60 2.4t. It’s has recently had a ignition coil replacement for a misfire (probably not important to problem). It’s has developed a problem where on startup in the morning (cold) it will idle very roughly and stall or almost stall (drops to 200 rpm and then jumps to 1000 to save itself). Giving it gas at this point will also cause it to stall as well as changing it into drive will either stall or make it idle roughly. But after warming up it up for a few minutes (around 10) it will run perfectly fine (turn on/off, rev, and change gears). I know it has a head gasket leak and am not sure if the coolant sensor works as it will read low coolant even when full. Any help or suggestions would be very appreciated. (Has 211k miles)

Edit: the message center in the dash sometimes does not work displaying only lines or distorted characters. Seems to work when coolant reservoir is freshly filled but will stop working soon after.

Edit #2: when misfire was detected the following codes were pulled:
p0303 (misfire)
p0234 (turbo charger overboost condition)
p2131 (throttle/pedal position sensor/switch F circuit ravage performance)
p0103 (mass or volume air flow circuit higher input)
p0353 (ignition coil C primary/secondary circuit)
p02101, p0202, p0203, p0204, p0205 (I don’t know what these are)

 

your P020x codes are injector codes where the ECUs senses something wrong in the voltage range for the injectors. Given all five has set a DTC, I doubt its the injectors and may be related to a relay or wiring issue (or perhaps a low system voltage event). I'd probably clear the codes and see what returns. The rough idle when cold is a sign that the fuel mix is off when cold. Areas to consider are MAF sensor, ETM, throttle posistion sensor, ECT (engine temp sensor), air intake leaks. The head gasket could also contribute if its leaking coolant into the combustion chamber (further cooling a cold spark). Your coil pack on #3 is likely bad (the P0303 and P0353 both point to the #3 coil). The P0234 says the wastegate is not properly actuating - could be mechanical (ie stuck waste gate) but a failed boost control valve will also cause this issue).

I'd start by replacing the #3 coil, inspect the spark plugs and consider refreshing if they are over 60K miles, clean the MAF and throttle body with some MAF cleaner, measure the resistance of the ECT (on a cold engine, it should be in the 3000-4000 ohms range - then drops to 200-300 for a warm engine) If your cold reading is 3K+, then I'd move on. The coolant level sensor is inside the overflow reservoir - you may need to replace the reservoir to fix it (some models the sensor is in the cap so its an easier fix on those). All of these can be done without investing more than $100 in a high mileage car that may need some major repairs so best to start with the small things to see if they clear up the codes and improves the driveability.

The suggestion that you have a head gasket leak is troublesome but without further tests you can't be sure. Your slow loss of coolant may actually be a slow leak in a radiator seam, heater core/hoses (does the heat come on with a sweet smell?), overflow reservoir or one of the hoses (including those that are hard to see under the intake). did you actually do a HC test (exhaust gas in the coolant) or have oil foaming (still this could be normal condensation) or oil in the coolant? Any white / light gray smoke from the exhaust (does the exhaust smell slightly sweet?)

 

The suspicion of a head gasket leak was because of the coolant system being empty everyday and leaking out the exhaust. We used some blue devil to see if it’ll do anything and it stopped leaking for half a year. Then we left the cap a little lose one day and it all spilled out. We replaced it with some coolant and it all came out through the cap in the reservoir. I’m assuming that exhaust gas is making its way into the cooling system and building too much pressure for the cap. We put another bottle of blue devil and it spilled a lot of it but it appears that sometimes some blue will be seen in the reservoir. (New radiator as well)

The spark plugs have about 2k miles on them and seem to be in good condition.

MAF was replaced a few months ago

Not sure if the coolant level sensor is working as it says low coolant even when freshly topped off. May replace

Will check the ECT resistance as it seems to be the easiest to check first.

The throttle body is somewhat tedious to get to so it’s going to be a last effort

Coil #3 was already replaced

Thank you for your suggestion and info!