so my car would every so often idle very rough and the rpm needle would bounce between 750 and 250. Now it’s everytime the car is warmed up so I️ scanned I️t and got a missfiring code in cylinder 5 and 6. I’m changing the plugs and cleaning the tb but I️ was wondering if I️t could be the coil pack. To my knowledge each coil pack fires 2 cylinders. I️ believe it’s cylinders (1 and 6) (5 and 2) and (3and 4)

 

Also got code c1201 engine control system malfunction

 

A couple of questions. Do you have a GS300 or GS400? What was the misfiring code you got?

 

1st try to burn that gas out or siphon it out. Sounds like u got water in your tank. Fresh gas & a treatment to absorb the moisture out the tank & change your coil packs.you should be good then.

 

 

 

Well lemme tell you. My 03 LX470 did the exact same thing. 2 cylinders were misfiring. Check engine was blinking, scanner said my cats are bad, it didn't cut off but was idled real low like yours in the 200rpm range. I changed my plugs & it still was stalling. Then I changed the 2 bad coil packs. Saw a video on YouTube about pouring lacquer thinner in your tank to clean the fuel system. Then drove the truck til it had like 2 miles to empty. Still misfiring, so I Pour a gallon of lacquer thinner in my tank & filled to 1/4th tank. I drove around on that mixture until empty & my light came on again then refilled with premium fuel. & during the drive it was hesitating & then like after 5mins of driving it stopped stalling, check it again with my scan tool & all the codes went away. CEL went off, cats are good. Ran normal ever since. I did this Feb 2017 Thinner has more cleaner solvents than regular gas treatments. Then it's excellent at absorbing moisture. Also clean out your throttle with throttle cleaner and a brush to break up that carbon build up. That'll cause your problem too! Hope this helps.

 

 

Well I can tell you this, I did it in February 2017 & today my truck still running strong. The trick is once you pour in your tank, cycle it thru your system. Drive the car until you empty the tank. Don't just pour it & leave mix with your gas & sit overnight. I'm telling you it cleaned everything. Injectors, spark plugs, O2 sensors, catalyst system. My scanner displayed everything in the green as good afterwards

 

What gas you were using when it happened. I fill up with only Shell premium year round.

 

I was running shell gas at the same time