Just threw a code p300 which I believe is multiple misfire. Havent done any mods recently but just developed a weird idle. Any suggestions on where to look first. The mods I have are

ur pulley
kinetix plenum
no cats
pop charger

 

that is multiple cylinder misfire, i would say check your cats but thats out, so next culprit would be to check your plugs/coils to ensure they work. then make sure your fuel injectors are working right.

try to put your oem cats on then clear the code and see if it works. if not start with some of the other suggestions.

 

I got one of those once after I put in cams and ecu. Just manually reset your ecu ( go to technosquare website for instructions), and you should be fine.

 

I have a code scanner and reset the ecu but have a somewhat bad idle still so there is still a problem. Its pouring out so Ill check the coils and plug wires tomorrow.

 

Well I started to look for my problem today. Opened my hood and first thing I saw was my kinetix plenum had cracked up top by the 2 screws. Hope once I get this replaced it solves my problem.