I replaced my idle control unit last winter when I would run into issues with it stalling out when going through car washes. I have noticed every now and then, I get a slight idle issue when driving at highway speeds (let off throttle and it drops too low before jumping back up).

Friday night I left the dome/bed light on all night. Therefore I had to jump it this morning. I did, and now the stupid thing didn't want to idle at all!!! I pulled the idle control unit and put it back on. Started up and she purred like a kitten. Go to drive down the street and as soon as I lift out of the throttle it stalls. Managed to get back into the driveway and this is what I found.

If I get the RPMs at 2000 for any period of time and let off the throttle, it drops all the way down below 500 RPMs and sometimes corrects it self and then idles at 750-800 RPMs. If I get up above 2000 for any period of time and then drop off the throttle, the RPMs drop down too low for the idle control unit to recover and idle, the truck just dies.

I see there is a little pin on the throttle body and it looks like you could screw it out to make it idle higher, but when I took off all the air intake parts to get to that pin, there is no screw head to make an adjustment.

I am so tired of dealing with this truck. I am seriously thinking about just getting it running to the point that it won't stall when a dealer takes it on a test drive and trade it in on something else.

How do you adjust the idle to a higher RPM?

 

The POS cheap "idle control unit" you bought could be defective. And if the battery went dead, it's normal for it to idle like crap or not at all until the pcm relearns. And I'd say you have a TPS issue also.

 

What is TPS? How long until the computer relearns? What do I have to do to help it relearn/drive down the street without it dying?

 

You may need to reset the idle air counts.

The bst way to done this is to use a scanner, but if you don't have one you can try this:

Turn truck on engine running and pull the brake booster hose off.
Wait5 sec, this will allow the iac valve to close.
Turn off engine unplugged iac and reconnect brake booster line.
TurnEngine back on and check the idle RPMs. They should be around 500. If not note the idle RPMs and write them down.
If not, open the thottle plates (or close) to set desired RPM (500). Its takes a # 25 torx screw driver and the set screw is by the thottle linkage. There may be a small metal plug covering it.
After it idles at 500, turn off engine and plug in IAC.
Restart and takes for a test drive.

 

yeah when i first got my truck my tps was bad and it hated to idle. TPS stands for throttle position switch. mine would jump rpm while holding the throttle at the exact same point and then when you let off to stop it would fall on its face and sometimes die.After i replaced the truck ran great

 

How do you get the metal plug out

 

That sounds exactly like my issue.

 

Ill caution you to be very careful messing with the set screw. You can bugger up your truck something fierce.

I would exhaust other possibilities first, like a new TPS or IAC before messing with the throttle set screw, but if you want to get the plug out, get a small screw and screw it in a few threads into the plug and pull on the screw head with pliers.

 

The MAP sensor could be failing as well... I have run into that before and had running issues so that may be worth keeping in mind while you are under the hood.

 

MAP = Mass Air ????

Where is it? How easy to replace?

Where is the IAC and how easy to replace?