Flashing CEL with P0300 and P0303

[jgue467]

Plugs gapped correctly? That was solution for OP in post#12 above.

Does your CEL flash? If so for sure let off the throttle - too much too long causes engine/cat damage.

Luck and enjoy the runner. :cowboy:

 

[Bigpapajeff]

Unbelievable.. same exact situation.. 98 4runnet 5z engine.. 275k .. just replaced wires,all three coils, plugs,both o2 sensors,maf,tps and 6 new fuel injectors!! We have had this truck for 20 years and would like to keep for another 20!! After replacing all of the above this weekend.. runs awesome for ten-15 minutes then the s$$t hits the fan.. flashing cel missfire cylinder 2..let it cool down and it the cycle continues.. at my wit's end.. what does the ECU do after running for 10-15 minutes?

I'm also having the same issues and have done exactly as you have. My 4Runner is also a '98 with about the same mileage. Did you find a fix for you's and if so, can you share it???