Cylinder 1 & 3 misfire when outside temperature changes

[tbendubois]

Hey all,

Quick summary: 1998 C230 - Car was running fine in -26C(-14F) and 30C(85F). Last year and this year car is misfiring 1 & 3 (this year for sure, didn't check codes last year) in transition temperatures -4C(24F) to about 7C(45F)

Long part: After car had troubles last year, ran fuel treatment, put in new spark plugs (bosch copper from the dealer), new fuel filter. Problems stopped for the summer and into winter. Now this winter it just started doing it again, after the temperatures warmed up a bit. Initially thought it was bad gas, then fuel humidity. Sometimes the car would be fine when it started, and just start doing it until the engine shut off, then be fine when it started again -- I heard the sensors reset until they detect a misfire and then shut down elsewhere on the forum.

I was hesitant about mechanical due to it working fine at the warm and cold temperatures, maybe a sensor issue or wiring? I'm going to double check the plugs and boots tomorrow when it is light out again.

EDIT: Car has 201200 KM. No service records other than what I have personally done to it.

I googled the issue and couldn't find much about the temperature change misfires, anyone able to shed some light on this problem for me? I'd like to know what it might be before bringing it to the mechanics here.

Thanks everyone.

[CJP28]

I highly recommend you change the ignition coils.

[Denlasoul]

I agree with above. Also, check the wires, maybe those particular ones are frayed.

[RemoLexi]

Without knowing codes, freeze frame data, or at least car information, all you can do is throw parts at it and 'hope' they fix it.

Possibly vacuum leak; coolant temp sensor acting up.

[tbendubois]

Sorry I never even said what car...brain fart there

I'm driving a 1998 C230
The codes were Cylinder 1 misfire detected, cylinder 3 misfire detected, and multiple/random misfires detected.

Thanks for the suggestions, I will check the coil wires tomorrow. When I was in there changing the plugs I noticed they were a little toasty but didn't see fraying (although honest I didn't look that close)

[RemoLexi]

I believe 1 & 3 are fired by the same coil pack. Swap coils and see if if goes to cylinders 2&4.

[tbendubois]

I went ahead and swapped the coils around and cleared the codes. Will report back if the codes do not change. Thanks for the troubleshooting suggestion RemoLexi

Of course today it ran fine for a bit, then acted up. After the coils were swapped it ran fine again, hasn't coded yet. I'd be surprised if the issue doesn't come back, but I hope it ends up being coils.

[tbendubois]

Thanks for everyone's help. I got the same codes on 1&3 last night after some highway driving, I assume it is the smaller orange boots that are the issue, I was planning on replacing them this week to see if that fixed anything when I woke up to this:



Needless to say I don't need to worry about engine problems anymore.....