I'm zeroing in on my cylinder #3 misfire problem (it's always the P0303 code) but am still stumped by one thing: it sometimes comes on after a heat soak, but why does it also happen after coasting downhill with my foot off the gas? The check engine light comes on flashing and the car misses badly. When I turn the engine off and start it again, the light is solid and it runs fine. Can the #3 injector really be overheating while driving? I fabricated a makeshift heat shield but haven't tested it yet. I'm not sure that the miss is actually a problem at the cylinder since it goes away by restarting, is there a limp home mode that may be disabling the car to prevent damage? Injector and spark plug are both good, I swapped them out. Can an O2 sensor affect just that #3 cylinder?

Thanks in advance for solving all of my problems. Next we can address my relationship...

 

Yes there is a limp in mode limits rpms to 2500 I believe

 

Thanks! That means I don't need to be looking for a bigger problem.

 

If it is a blinking Check Engine light, its a catalyst damaging misfire, so it should be ignition related.

 

Drat, how can that be? I guess I have two problems, although they must be related. The light doesn't flash for the heat soak misfire and it runs fine but it does flash after coasting and then it actually misfires or is shut down by the computer. How can I be having an intermittent ignition problem on only one cylinder? I've already tested and ruled out the plug. The coils each run two cylinders and the other cylinder never misfires, only the #3. I'm going to experiment with stealing my shop vac hose and rigging it up as a duct to blow outside air over the injectors to see if keeping them cooler makes a difference. Is this where the hood vent I've read about comes in?

 

I was having these problems too and there's an update to the computer I got done at a dealership that fixed the problem.

 

Thanks, I'll call the dealer and see what they know...