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3.9 Magnum IAC continues to need reset

I own a '96 Dakota with a 3.9 Magnum (V6) and my truck will die due to low idle whenever I start it after the engine has warmed up. The first start in the morning is fine and if I wait 4-6 hours it will start up fine again, otherwise I have to give it constant gas to keep the RPM up and drive with two feet for the first block or so, and it comes out of it.

The fix is to press the Idle Air Control (IAC) all the way back in every 5 days. Doing this causes my idle RPM to be substantial to keep my truck running without giving it any gas. After about 5 or 6 days it starts to get sluggish then same results. I have this issue through late fall to early spring. Summer months is seems fine.

I have replaced the IAC twice, and it solves it for a good week then acts up again. They don't appear to be defective or gummed up. My only guess is something that control the IAC is not doing its job.

My mother who has a '95 Durango with a 4.7 Magnum has a similar issue. Related to the IAC perhaps. Her problem just started this winter. The vehicle starts and idles fine, but when in gear - say backing out of the driveway it will stall and die. I do not know if she were to drive with foot on gas to keep RPM and foot on break would work or not as it does for me. But the fact she has decent idle RPM's means it is working to an extent. After replacing her IAC she had no problems for about 3 weeks, not acting up again.

Those who have posts in here saying the IAC fixed there solution seem to be sincere, and don't come back saying it doesn't work again about a month later. I find it strange both engines have this issue. Is it a Throttle Position Sensor? Do these even have one to replace? My thoughts were something with the computer but I don't want to spend that money unless it is absolutely guaranteed to be the problem.

Thanks for any input.

*Engines have kept up with being maintained and parts were purchased new, not used.

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