Idling n RPM problems
If you don't have power brakes and it has recently started running bad it was probably capped and it fell off.
The reason it messed with your idle is this.
The MAF (mass air flow) sensor (along with a few other sensor)tells the PCM how much air is entering the engine. The PCM then add's the required amount of fuel for the combustion process. After that the oxygen sensor monitors the exhaust for oxygen content. If there is more or less fuel than what the PCM is expecting it tells the PCM, hey we need more or less fuel.
Because the un metered air(air not seen by the MAF which then can't tell the computer)the oxygen sensor "thinks" the exhaust mixture is lean and then tells the PCM it needs more fuel even though it really doesn't.
The larger the vacuum leak the more fuel the PCM will add.
I hope at least some of that makes sense.
Thread Starter
Teching In
Joined: May 2015
Posts: 10
Likes: 0
From: California
So much knowledge here! I'm assuming since I have hydraulic steering and a brake booster as well, is the reason I'm not using the vacuum hose, and that's why it's capped off. Thanks for all the help with trouble shooting and detailed explanations. Thank You!!
Last edited by Hogsters; Dec 12, 2015 at 02:44 PM.
