hey guys i drive a 2001 Z24 and i just put a new engine in it seems to be idling hi not too bad but at like 1500 before it was about 1000 but my gas mileage has gone way down i was easily getting about 30 and now its like 23 is the engine probably still just breakin in or what?? i removed the air intake and checked my throttle body and it appears to be shutting like it should when no gas is pressed what else can i do???

Check the IAC motor cause if its not closeing properly it'll cause the high idle. Also you say you just did a swap are you sure you have NO vacuum leaks anywhere cause that'll do it too.




Semper Fi SAINT. May you rest in peace.

Jackalope wrote:Check the IAC motor cause if its not closeing properly it'll cause the high idle. Also you say you just did a swap are you sure you have NO vacuum leaks anywhere cause that'll do it too.

Yeah if you had a scan tool and it said the IAC count was like 0. And you still had a high idle, then you have vacuum leak, because the computer is doing all it can to compensate for the extra air ( ie closing the IAC all the way)




- 2004 Cavalier - 124k, owned since new

what year engine did you put in? did you use the 01 injectors?

I'm asking because 96-99 had 24lbs injectors and low pressure (well 35-43psi) and the 00-02 had higher pressure and 19lbs injectors. If you are using the 24lbs injectors with high pressure, it's enough to make the idle higher.



Gilles
2.3 Ho