Different Search Results on IAC Testing

[KW021]

I have been searching all over for many hours and days now and have come across some conflicting ideas as to whether or not I have a bad IAC.

I am having idle surge problems when my EX is cold (sits overnight and below 40 F outside). Somtimes it stalls if i don't give it gas for a little bit, but it always sputters enough that the whole truck is shaking. When it warms up a little bit the idle evens out and its fine. Once and awhile it will surge when its warmed up but not to often and its very minor. I have also noticed a loss of power and drop in fuel economy since the check engine light came on...I get roughly 17mpg, I accelerate slowly and set cruise at 66mph on highway to save as much gas as I can.

I tested the IAC and passed 2 out of 3. Voltage from the wire harness was good and the ohms between the 2 pins on the IAC was 9.5ish. When I did the test from one pin to the IAC casing and it read OL...so I figured the IAC is bad. Then I read something else about unplugging the IAC to see if the idle changes. My EX stalls out immdiatelty when the IAC is unplug which from what I read means it is functioning properly.

So I don't know if I should spend $85 on a new IAC or not.

So far I have replaced the Fuel Filter and MAF sensor with no improvements. I have also sprayed some carb cleaner around a bunch of vacuum hoses and haven't been able to find a leak yet.

I'm not sure how old the plugs and wires are and I don't know if the manifold gaskets where ever replaced. It has 72K miles and i bought it from original owner who seemed to take good care of it.

 

[Sams01XplrSprt]

welcome kw021

 

[Cobraguy]

IAC issues are just as common from being dirty as going bad. But they do go bad too. They aren't able to respond to the ECM commands properly. I would try cleaning everything, and if no go, replace it. This is assuming you don't have any vacuum leaks anywhere. That's always the first thing to confirm!

 

[KW021]

Is there a way to confirm if the intake manifold o rings are leaking. Would propane or carb cleaner get sucked in through those?

 

[Texan01]

Mine had the same issue for a while, turned out be several problems, a marginal MAF sensor, dirty TB and IAC and after several years of ignoring it, a vacuum leak caused by a hole melted into the upper intake from the EGR sensor hoses falling off.

Check the intake for vacuum leaks, tighten all the bolts up the recommend sequence. You can spray water, WD-40, Carb cleaner, Windex, just something in a spray bottle to seal the hole for a bit. Just make sure whatever you use has a good tight spray pattern to help locate the hole.