Random missfire code came up for bad coil pack I changed that and the spark plugs. Now I'm getting a p0300b code which is random miss fire. I know that could mean alot of things but the missfire is at idle and low speed any idea where to start

If the light is flashing its because your doing damage to the catalytic converter. Your dumping raw fuel, in other words you have a coil pack not firing. Your gonna have a P code. Either P0300 random multiple misfire, P301 cylinder 1 misfire, P302 cyl #2 misfire, ect... Replace the coil pack on the dead cyl.

that pertains to random secondary ignition missfire.possibbly another code to help pinpoint which cyl. is missfireing po304 #4 cyl. spark plug,boot/wire coil/or individual coil pack,ignition module.check in that order.need more info year,vin,etc.

a random miss fire can be caused by many things but the cheapest & easiest place to start is change the spark plugs & wires & distributor cap & rotor if equip. or check coil packs

The firing order is 4 1 2 3 it's from left to right looking at the ignition coil

Hi Jamie, I cannot find that fault code! I suggest that you look at the coil packs which control the ignition and the crankshaft and camshaft sensors. These are the areas most likely to cause random misfire. You should also look at the condition of the spark plugs. Fitting a new set wouldn't be a bad idea, but get the recommended plugs of the correct heat range and type. Regards John

better look at the blender door. this is a vacuum controled door that allows hot or cold air to flow into the HVAC system and blends the temps together to make the desired temp for you, but if this is electronicly controled you might have a temp sending unit bad or even a control unit bad, as for the miss fire most people wouldn't know a miss fire from a bump in the road anymore. engines anymore if there is a missfire code, there is a missfire, find out what cylinder if missfiring and replace the sparkplug, wire, or coil, you can have the wire loaded to see if its the spark plug or not, and then get the coil tested as well, this will say you money inthe long run since replacing random parts if a waste of money on your part. test it and find the failing part and replace...

cylinder 2&3 misfiring, inspect plugs if ok, mark and swap coil packs for known good ones clear codes, run eng brake torque it rev to cause missfire, repeat until check eng, lite comes on, recheck codes if changed cylinders replace coil packs if not, you have two bad injectors.

You still have random misfires (PO300)
You most likely replaced those coils that set a code, and those were not the one bad offender,spiking the computer module.
Take a new coil and put in a cylinder,no change, replace old coil and move new one to next cylinder. You can do that once or twice a day, if you have nothing else to do. You need a 90 degree day, to really get that solved,unless you have an ignition oscilloscope.
Never had a bad spark plug in 45 years.

check or relace your coil pack due to the fact that when a coil pack is going bad it usually looses its umph. when it get hot and that would explain random miss fires

It sounds like fuel starved at higher speeds. i would change the fuel filter first if this does'nt help check the fuel pressure