IAC needs replacing?

[AOSJ]

@macleanflood @hear idle gremlins update. Got her back from the mechanic. had a smoke test done and all the electrics checked. did a throttle sensor re-calibration. Found a leak by the evap canister. picked her up and the idle was good. dropped below 700 a couple of times. But she drives great now. called them about the drop and they advised, if it goes batty again, its the ECU. what do you guys think? gonna check her out for the next few days and see what surprises, if any, come up. Cant wait to get to the point of driving without the fear of a stall.

my 2001 4.0 idles at like 500rpm when warm, if it idled at 700 warm I personally would be looking at my throttle mechanism to see if something is causing it to be open a hair, but 700 may be normal for you

 

[jayeljeep]

@macleanflood @hear @TJ Jim heres a vid on the idle flux... and one vid right after where it wont start. I'll give it a rest, then it'll start and drive fine.

View: https://www.youtube.com/shorts/F-fQVfOyfZ8

View: https://www.youtube.com/shorts/uX2sXqRwiB0

 

[macleanflood]

Again...I'd check and make sure your intake bolts are properly torqued.

I'd check all your IAT wiring. Continuity and ohm checks back to the PCM connectors.

Most importantly I'd be logging live ODB data through the anomalous idle. Knowing what the computer is seeing and doing is important.

-Mac

 

[TJ Jim]

Just spit ballin here. If you’ve got a multimeter I’d look at the p0128 fault that you had awhile back. The multi meter can show you if the tps is flaky. If you really want a clear picture of the tps operation a Simpson 260 meter will paint a very clear picture.

A second thought is I wonder what your fuel pressure is? Do you run you tank mostly full or mostly empty?

Like @macleanflood suggested look harder for vacuum leaks.

 

[Hacker412]

If you have an ODBM reader, try clearing the codes. Even if it does not have any popping up.

 

[TJ Jim]

@jayeljeep

View: https://youtu.be/5X-SaTrQgjw?si=tSydc-E0tdv81J07

 

[TJ Jim]

ODBM reader

??

 

[TJ Jim]

Tps p0128 symptoms:

• Check Engine Light
• Hard start situation
• Erratic idle
• Engine stalls
• Weak acceleration
• Decreased fuel economy

 

[hear]

??

He meant OBDII reader. Life is harder for some people than it is for others.

 

[jayeljeep]

Again...I'd check and make sure your intake bolts are properly torqued.

I'd check all your IAT wiring. Continuity and ohm checks back to the PCM connectors.

Most importantly I'd be logging live ODB data through the anomalous idle. Knowing what the computer is seeing and doing is important.

-Mac

Thanks @macleanflood will do

 

[jayeljeep]

Just spit ballin here. If you’ve got a multimeter I’d look at the p0128 fault that you had awhile back. The multi meter can show you if the tps is flaky. If you really want a clear picture of the tps operation a Simpson 260 meter will paint a very clear picture.

A second thought is I wonder what your fuel pressure is? Do you run you tank mostly full or mostly empty?

Like @macleanflood suggested look harder for vacuum leaks.

@TJ Jim. Thanks for the info. I run her always at least half tank or above. Im gonna try out the multimeter. Truly grateful for the advice. Much mahalos.

 

[jayeljeep]

If you have an ODBM reader, try clearing the codes. Even if it does not have any popping up.

@Hacker412 Thanks for the advice. Ill try it. Much mahalos

 

[TJ Jim]

He meant OBDII reader. Life is harder for some people than it is for others.

I’m old and easily confused so sometimes I gotta ask for clarification.

 

[jayeljeep]

Should I reset the ECU? I cleaned the IAC. But didn’t reset. Or buy a new IAC?

 

[jayeljeep]

she fully stalled. Towing back to mech.

 

[TJ Jim]

Fuel pressure. Fuel pressure. Fuel pressure.

 

[jayeljeep]

stall in intersection. dropped idle then wont start. heres some vids...


View: https://www.youtube.com/shorts/TUaXnZcLnn0


View: https://www.youtube.com/shorts/mJzkiUUQwWA

 

[hear]

Nope. Drive it like you stole it.

-Mac

Like a glass of raw milk on a warm summer day.

 

[TJ Jim]

Don’t see the tach needle moving? Isn’t that a sign the crank position sensor is bad?

 

[hear]

Don’t see the tach needle moving? Isn’t that a sign the crank position sensor is bad?

This is a thing I've heard said, mainly by one person who took his ball and went home. I would love to have this proven or disproven once and for all.