bad idle

[brueman554]

early morning starts or even 15min after driving after starting itll reve high then slowly go down sometimes just completley turns off? other times itll stabilize and as soon as i hit the gas it dies whats the probem?

 

[XiKeiyaZI]

This can be caused by several things, the most common of those being a boost/vacuum leak. So first and foremost, go ahead and perform a boost leak test while spraying everything down with soapy water and repair any leaks that you find in the charge/intake system.

This is not the only thing that could be wrong, however. A lot of times you will encounter improperly adjusted throttle body's. I recently helped a good friend resolve her idle issue - during decel the engine would bog and try to die, struggling to maintain 500+ rpm. Her TPS was reading .96 instead of the called for .63/.64 range. We went ahead and adjusted the throttle plate screw to 2 full turns from fully closed, set the TPS correctly, and turned the BISS screw out 1 1/2 turns from all the way in. Car started right up, idled high for a moment, then leveled out. It now decels perfectly with no idle hunting at 950rpms, and idles much smoother.

Aside from the TPS, the BISS can make a huge impact. If it is improperly set the ISC will have to work extra hard and may not have the lee-way needed to maintain a good idle on decel, thus bogging and/or dying. Making sure the BISS is set properly and your ISC is in the proper range (30%-35% if I recall correctly at idle?) is also a very positive thing to check into.

Just some food for thought.

 

[brueman554]

i checked for boost leaks right before posting this thinking tht could be the problem but its not, then i thought it could be something power related due to the fact it dies even faster if i turn on the headlights or power up the radio, and at a complete stop the car will die if the ac is on

 

[Backinajiffy12]

have you checked the alt. yet?

 

[XiKeiyaZI]

i checked for boost leaks right before posting this thinking tht could be the problem but its not, then i thought it could be something power related due to the fact it dies even faster if i turn on the headlights or power up the radio, and at a complete stop the car will die if the ac is on

Well, time to start checking your charge system then. Check battery condition, alternator output, and electrical connections.