[johnson93gt]

I have a 2004 focus that runs pretty good when idling but as soon as you put it i gear it shakes bad. when you turn the ac on it tries to die. There is no check engine light on.The plugs look really lean. I have 40 pounds of fuel pressure and it holds for 30 mins after turning the car off so i dont think thats it. Im sure a sensor is causing the problem by not reading right but i cant seem to track it down. thanks in advance for any help.

 

[zetecDon]

Moved to "General Technical Chat".

 

[sailor]

You didn't happen to mention the engine type for help pointing to the part location, but it sure sounds like an IAC that isn't working well causing a drop in RPM when put in gear or A/C turns on.

If it doesn't idle high when cold, the IAC is doing nothing at all.