Need help with idle.

[DeclansDaddy]

After putting new head gaskets on my '95 3.0 everything seems ok except for the idle. Upon start up the idle is fine 700-800 rpm. As the truck warms up it idles up slowly. At operating temp the truck idles at 1400rpm.

I initially thought vacuum so we replaced every inch of vacuum line which changed nothing. Every time I've ever had a vacuum leak it made it idle high even when cold so is there something else that could be causing this?

 

[penbergm]

First off, your idle at cold should be higher than 700-800. I believe the idle control valve is built into the throttle body on the 3.0. However, this would decrease your idle after it warms up.
Have you checked to make sure your TPS is adjusted correctly? Also make sure timing is set correctly using the jumper in the diag port.

 

[Ahlem]

I have a similar situation but not having changed headgaskets.
In the winter I have a high idle all the time at about 1300-1400.
In the summer I start out idling properly but when the truck warms up and you turn it off then re-start it, the idle is so low it dies. You can sit and hold the idle for about 2 minutes and then all is well.
I did reset the timing and the TPS is checked and functioning properly.
My suspicion is that one of the temperature sensors is gummed up. I know of the one on the throttle body and it's gotten a shot of carb cleaner. I think there is another one on the back of the motor but a previous post from last spring yielded no intelligent replies. I will be interested to hear the answer to this.

 

[DeclansDaddy]

I'll check the tps although I don't believe we messed with it during the HG install. As for timing yes I timed it with the jumper wire. I set it at 10* per FSM however I've always been taught to time at operating temp which is idling at 1400 so I'm sure that's not accurate. Just to check I timed it cold while it was idling low and it didn't help.