well, it's really 1 worry and 1 question. My worry is why does my engine rpms jump from 1500 to 2000 back to 1500 then back to 2000 over and over for about 5 seconds when ever i start my car in the cold. Also, i would like to know why i can't go past 7000 rps and my vvtli won't kick in if the engine isn't warmed up.
1) your IACV is dirty. refer to the garage installs engine forum for the writeup I made on how to clean this properly. It shoudl solve your idle problem.
2) there is something called a neutral rev limiter in our cars. it kicks on at 7,100 rpms. (if you were to put you car in nuetral and slam the gas down, you'd bounce off that limiter nad never get higher.)This limiter also get tunred on a few other ways.
a) when the engine is cold
b) when in nuetral
c) when you get too much wheel spin. (the ecu goes into a safe mode thinking your car is free reving when really you're simply spinning th etires too much, too fast.)**this typically only happens on hard launches when racing**
hope that helps