Rough idle?

[gagebruv]

Tonight I was sitting in the drive through and all of a sudden the car started shuttering aggressively. The check engine light started flashing and I didn’t know what to do. Then about a minute later it started idling smoothly again and the check engine light turned off. It drove home normally but I didn’t rev it higher than 3k out of paranoia. Couldn’t find anything hardly anything online on this issue. Don’t know if it’s gonna happen again or if it
needs addressed. Hoping it’s nothing major and just needs some new spark plugs, it seemed like a misfire to me. Hoping someone on here knows what this could be. The car has an intake and cat delete as well.
Edit: Code reader gave P0301 cylinder one misfire. Must just be a bad plug I’m guessing.

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[SHOdded]

MY, mileage? flashing cel means misfire. plugs or injectors. looks like its time to do plugs, and note if any are wet with fuel also.

 

[gagebruv]

MY, mileage? flashing cel means misfire. plugs or injectors. looks like its time to do plugs, and note if any are wet with fuel also.

Cars got roughly 96k miles, the plugs probably were never changed before, I’ve only owned the car for a few months I had a shop go over the motor and addressed most of the problems with it when I got it. It’s more than likely a coil pack or plugs. I’m just gonna check the plugs and see if they need replaced.


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[GTRPhilly]

Cars got roughly 96k miles, the plugs probably were never changed before, I’ve only owned the car for a few months I had a shop go over the motor and addressed most of the problems with it when I got it. It’s more than likely a coil pack or plugs. I’m just gonna check the plugs and see if they need replaced.


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I got the same issue and I’ve replaced my plugs and cleaned all map sensors. Doing the throttle body today. I will let you know.

 

[SM105K]

Cars got roughly 96k miles, the plugs probably were never changed before, I’ve only owned the car for a few months I had a shop go over the motor and addressed most of the problems with it when I got it. It’s more than likely a coil pack or plugs. I’m just gonna check the plugs and see if they need replaced.


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Move a coil pack from the cylinder that is missing to the one next to it. If it moves, then the coil it likely suspect. If it doesn't move, then check the spark plug.

 

[luigisho]

I have also heard of doing this with coils, plugs and injectors when looking for causes of cylinder miss. Just food for thought. I do the coil thing first and if the plugs are old just do them all anyway. Then injector if still looking.

 

[GTRPhilly]

Ok. I did my throttle body today and noticed a pretty big difference. Put it this way, my first stop I thought the car stalled. I disconnected the battery during the whole procedure for re-learn. Took a little to smooth out and now it’s quite a bit better. This doesn’t mean it’s everyone’s issue, but it was definitely part of mine. Good luck.

 

[GTRPhilly]

Just for reference I did plugs, cleaned all map sensors, cleaned throttle body and put a bottle of AMSOIL fuel system cleaner or some shit. All this seemed to work for me as I mentioned above. The throttle body being the biggest difference or just happened to be the order of operations I did.

 

[SHOdded]

if throttle body makes the biggest difference, i would look at the map sensor in that location as well as scope the intercooler for the fuel/water/oil crud that tends to accumulate in there.

 

[gagebruv]

Just for reference I did plugs, cleaned all map sensors, cleaned throttle body and put a bottle of AMSOIL fuel system cleaner or some shit. All this seemed to work for me as I mentioned above. The throttle body being the biggest difference or just happened to be the order of operations I did.

I haven’t had the chance to mess with it today, but when I drove it today it didn’t have any issue. I’ll look into that and see if that’s causing any issues as well, if the plugs/coil packs don’t resolve it.


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[kryptto]

Be careful cleaning the MAP sensor do not use carb cleaner - use map sensor cleaner. The filament can be easily damaged.

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[Junkyard_Mad-Scientist]

I have had a misfire gremlin for as long as Ive had the car, always a random misfire followed by a sensor 1 code, its usually bank 1, sometimes bank 2, and if it identifies which cylinder it is its almost always cylinder 2 but sometimes its 6 sometimes or 5. i did the move the coil around, checked the plugs, down the rabbit hole and back up empty handed. until one day it did it to me sitting a stop light and i got to the plug in time to see an EVAP code. I restarted the car, still rough idle, I cleared the code, still rough idle, thinking I was stranded I left it running and wiggled the lines going to the evap solenoid and it smoothed right out. the last 3 times its happened since it still only throws a misfire and o2 code, the evap code has not come back BUT if I stay out of the throttle for about a minute, it sorts itself out and goes on like nothing happened. I call it Tori's tantrum, she shakes and bogs down, cel flashes, so I let out and wait for the light to stop flashing and its over. seems to happen more on wet days (not even rainy, just humid). I have to check to see if i have an o2 wire maybe burned but i'm still thinking it might just be the EVAP solenoid. sorry for the long post but sounds like youre having the same issue and thought I'd share my saga. good news if its intermittent its probably a wire or sensor and nothing major

 

[gagebruv]

I have had a misfire gremlin for as long as Ive had the car, always a random misfire followed by a sensor 1 code, its usually bank 1, sometimes bank 2, and if it identifies which cylinder it is its almost always cylinder 2 but sometimes its 6 sometimes or 5. i did the move the coil around, checked the plugs, down the rabbit hole and back up empty handed. until one day it did it to me sitting a stop light and i got to the plug in time to see an EVAP code. I restarted the car, still rough idle, I cleared the code, still rough idle, thinking I was stranded I left it running and wiggled the lines going to the evap solenoid and it smoothed right out. the last 3 times its happened since it still only throws a misfire and o2 code, the evap code has not come back BUT if I stay out of the throttle for about a minute, it sorts itself out and goes on like nothing happened. I call it Tori's tantrum, she shakes and bogs down, cel flashes, so I let out and wait for the light to stop flashing and its over. seems to happen more on wet days (not even rainy, just humid). I have to check to see if i have an o2 wire maybe burned but i'm still thinking it might just be the EVAP solenoid. sorry for the long post but sounds like youre having the same issue and thought I'd share my saga. good news if its intermittent its probably a wire or sensor and nothing major

Turned out to be an AFR issue. The car was reading temps wrong and making cylinder 1 run too rich. Changed the plugs and had the car relearn itself and that seemed to fix it.


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[marshallma0504]

Tonight I was sitting in the drive through and all of a sudden the car started shuttering aggressively. The check engine light started flashing and I didn’t know what to do. Then about a minute later it started idling smoothly again and the check engine light turned off. It drove home normally but I didn’t rev it higher than 3k out of paranoia. Couldn’t find anything hardly anything online on this issue. Don’t know if it’s gonna happen again or if it
needs addressed. Hoping it’s nothing major and just needs some new spark plugs, it seemed like a misfire to me. Hoping someone on here knows what this could be. The car has an intake and cat delete as well.
Edit: Code reader gave P0301 cylinder one misfire. Must just be a bad plug I’m guessing.

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My SHO has 114k on it and I had a flashing CEL under heavy acceleration until I did my plugs. Make sure to gap them to 0.028 for proper ignition. One of mine had grown to 0.040. After doing the plugs the car was way smoother at idle and under any % throttle. Plugs are a must on this engine as it gets very unhappy it seems when the plugs age. MAP sensor cleaner is my next maintenance item as well as draining the intercooler.