3VZE High Idle

[mjquillici]

When cold, it idles high, like it should. As it warms up, it still idles well over 1250 RPMs. After driving for 15 to 20 minutes, it will finally settle down to about 1000 RPMs, but that's as good as it gets. Is this a vacuum issue? What's the best way to trouble shoot? Pull one vacuum line off the intake at a time, plug the hole, and see what happens?

 

[92-SR5]

Have you tried to manually adjust the idle? Usually vacuum issues cause surging idle.

 

[mjquillici]

My rationale was that if it has been idling fine and then began idling high, that something must have happened to cause the change. . .

 

[77'911]

I would check the timing first, then vacuum leaks(intake, injector, etc..). If the fuel pressure is low, the stream into the cylinder can result in slightly raised rpms, depending. You might clean the throttle body and check the idle screw (make sure it has not walked out).
regards

 

[Blueaussie]

I would check the timing first, then vacuum leaks(intake, injector, etc..). If the fuel pressure is low, the stream into the cylinder can result in slightly raised rpms, depending. You might clean the throttle body and check the idle screw (make sure it has not walked out).
regards

I am sorry for piggy backing here...lol but 77'911 you sparked my interest.
You mentioned to the OP on the above. I have a 95 3.0L and I feel stupid in asking, but is the idle adjustment the top screw on the throttle body, From what I gathered from the FSM it is but my local mechanic tells me that that top screw is for air mixture. I may have done something really stupid by adjusting that. I am concerned that iif in fact it is for air to fuel ratio I fear it may not pass inspection and I might be loosing some performance / MPG especially since I just put a re-manufactured engine in about 7000 miles ago. Thanks for your help or anybodies for that matter and my apologies to the OP
Thanks:rockon:

 

[77'911]

I am sorry for piggy backing here...lol but 77'911 you sparked my interest.
You mentioned to the OP on the above. I have a 95 3.0L and I feel stupid in asking, but is the idle adjustment the top screw on the throttle body, From what I gathered from the FSM it is but my local mechanic tells me that that top screw is for air mixture. I may have done something really stupid by adjusting that. I am concerned that iif in fact it is for air to fuel ratio I fear it may not pass inspection and I might be loosing some performance / MPG especially since I just put a re-manufactured engine in about 7000 miles ago. Thanks for your help or anybodies for that matter and my apologies to the OP
Thanks:rockon:

They (the engine rebuilders) should have set the idle before sending out the long block/complete in most instances. There are a multitude of things can set the idle high. That screw towards the top of the body can and does walk out from time to time. If your f-pump and or regulator are starting to go, that can kick up the idle by not properly atomizing the fuel into the cylinder. Did the engine come with the distributor installed? If not check the basics first. Once that idle is properly set, the truck will also shift much smoother. You might ohm out the O2 sensor as they can have an effect on MPG and idle. If you don't have a factory manual set, you might consider buying one. Well worth the $$.
regards

 

[Blueaussie]

They (the engine rebuilders) should have set the idle before sending out the long block/complete in most instances. There are a multitude of things can set the idle high. That screw towards the top of the body can and does walk out from time to time. If your f-pump and or regulator are starting to go, that can kick up the idle by not properly atomizing the fuel into the cylinder. Did the engine come with the distributor installed? If not check the basics first. Once that idle is properly set, the truck will also shift much smoother. You might ohm out the O2 sensor as they can have an effect on MPG and idle. If you don't have a factory manual set, you might consider buying one. Well worth the $$.
regards

I believe mine was just the long block from ATK Nort America and shop just put on all other parts that came off the one. I have a FSM and I could swear it said that top screw was idle adjustment. but the shop tells me no. I will check the 02 sensor Thanks