This shouldnt be happening...

[06RangerXLT]

so, i think my IAC has gone to shit, or is on its way. when i fire the truck up after sitting for about 8 hours, it revs up to almost 3000, makes a nasty noise then goes to the regular high idle till it warms up. so thats one problem.

my other problem is when it finally calms down and drops to regular idle, its at just over 1000rpm. and its idling rough. normal for my truck is right around 650rpm. now not shaking the truck side to side, but enough that it will slide my ipod off my dash. never would before.

once it warms up, the problem doesnt exist. it fires up fine, idles ok, and runs at the correct RPM.

ive recently cleaned the MAF and IAC, they are plugged in correctly, and there are no codes. my guess is it still in tolerance. when i had my missfire, it took a good 30 seconds of bad running before it caught on and light up a CEL

also, i can tell its high for the idle, because just letting my foot off the brake takes me trough first and into second gear.

Thanks a ton guys, im not to up to date on the computer systems in these trucks.

 

[adsm08]

You don't by chance have a manual transmission do you?

 

[Insanejughead]

You don't by chance have a manual transmission do you?

His signature states that it is a 2wd auto...

 

[adsm08]

His signature states that it is a 2wd auto...

Hah, do it does. I looked for that everywhere but the sig.

Too bad. I know for a fact that there is a PCM update for the 06 4.0 manual for just this type of thing. High or erratic idle.

I don't know if there is one for the auto, but I doubt it because when they apply to all transmission types, the TSB doesn't usually specify trans type.


Still, 06, if you PM me your VIN I'd be happy to look for messages about your issue that actually apply to your truck. But yeah, IAC is high on the list of suspects since it goes away at temp.

 

[06RangerXLT]

You don't by chance have a manual transmission do you?

No sir, it's automatic. What do you think?

 

[06RangerXLT]

Ok I'll grab the vin and pm it over I'm a few. How much does an IAC run usually?

 

[Insanejughead]

I would personally recommend to see if it just needs cleaned first. They're pretty simple, and I take carburetor cleaner and spray the inside until I get all of the gunk out.

 

[06RangerXLT]

I just did that last week.

 

[DRanger024]

check for vacuum leaks as well. I had one that created a very rough idle on a cold start up and seemed to magically go away when it warmed up. Check the elbow below the left side of the throttle body. the intake tube pretty much sits on it and will eventually cave the foam/rubber elbow and make a hole about an inch and a half long. This particular elbow has an approximately half inch plastic tube running into it from the the back side of the intake.

 

[06RangerXLT]

It's more of a sputter then that kind of rough idle. It's spitting I think.

 

[racsan]

i had a vaccum leak a few years back that caused weird idle issues, would rev up between shifts too (mines a manual trans) turned out to be the fuel rail gasket had "pulled" in, front & rear. yours is new enough that maybe you could gain info from a scanguage. mines obd1, while i dont much care for alot of the newer technology, obd2 does help you get to the bottom of things a bit better (sometimes) with my obd1, its count the flashing light. i dont recall even have a c.e.l. when that problem happend. i went through the replace this, replace that, and i was down to the main processor or tear down the top end and look for vac problems, the good news is i have all new sensors and i kept everything i changed.