High idle rpms please help!!!

40

Asked by GuruD4J8D Aug 04, 2017 at 12:08 AM about the 1996 Ford F-150 XLT 4WD LB

Question type: Maintenance & Repair

my truck idled at 2,000 rpm then after a while it would go down then want to go up
again, i looked online and saw that people normally changed the idle air control
valve so i got a new one, but i still have the same problem,i played with the idle
screw and got it down to about 1,100 rpm. I unplugged the IAC  and the truck runs
great low idles rpms and everything, i took it for a test drive (plugged the IAC back
in) and when i push the clutch and hold it there the rpm went up it hit 3,000. also
when i let go of the gas pedal the rpms are still up and the truck goes by itself.  
Could my problem be the throttle positioning  sensor, also i checked and there
doesn't seem to be any vacuum hoes leaks.

Been looking for possible solutions for hours but got nothing i would really  
appreciate  it if someone could help me.

10 Answers

330

it would be hard to diagnose without seeing the actual car, first thing to check is if there a "check engine" light, that might give you a code that makes it a lot easier to check, check the throttle body if its dirty but it could be many different things, its best to have a mechanic look at it instead of just wasting money on part trying to guess the problem

10 people found this helpful.
40

no there wasn't any check engine light before i replaced the IAC, i will probably have to end up taking it to a mechanic whenever i can afford it, I appreciate you taking a look at my question tho

4 people found this helpful.
140

i have a 2001 Ford F150 V8 it is also idling too high it goes by it self at 35 miles a hours it starts great when it is cold but you have to put the peddle to the floor it starts right up but will not idle down to less that 2 grand. the guy that works on my truck says fuel pump?? I took it to discount auto got a code P0113. He doesn't think it is that. Any suggestions please email me at slusmeyer.kimberly@ifoodgroup.com

14 people found this helpful.
260

I had the same issue, it turned out to be the temperature sensor to the computer, not the sending unit to the gauge. The sensor is located in the front of the engine, below the top radiator hose at the thermostat housing.

26 people found this helpful.
90

I have a 02 ford king ranch 4.6L 2W drive i just put another Transmission in it and realized at my lines was leaking so on my way to go get them fixed my truck started idling at 200 RPMs and the transmission is slipping but it's showing full on the dipstick

9 people found this helpful.
50

my 02 5.4 f150 idles up to 2400 rpm every time u started it , would come down eventualy , when cold in winter it stay high longer than i thought it should. anyway came across a video where the guy put a cardboard gasket on the iacv with 2 holes punch in in each port, bout the size of a pencil, i did this, now when i start it up cold i rev it up to 1000 to 1500 rpm for a while, then it idles at 700 rpm after its warmed up. now when i rev it the rpm drops immediately when i left off the throttle before it would take about 4 seconds to drop down. im sure i'll need replace the iacv eventually

5 people found this helpful.
50

Lower intake manifold vacuum leak will make it idle really high , especially at startup.

5 people found this helpful.

the website erased my answer which had the solution and i am not typing it again. That is a problem with the Internet kids: you are screwed because of control freaks.

20

Cravinbob what was the solution? I’m having high idle on a 02 f150 5.4L and have tried everything people have mentioned on here with no luck

2 people found this helpful.

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