I have a 2000 F150 5.4L with less than 50,000 miles on it. This has happened twice in the past couple of months. The engines starts but then dies because of no idle. No check engine light. The first time it happened I was able to get it into gear after 4 or 5 starts and once it was driven for a couple of minutes the idle returned. It happened again today. It started, died, and then I was able to start it again and it stuttered abit and the idle caught. Anybody have an idea as to what this problem is? I have tried the search with little luck. Thanks

 

Sounds like a sticky IAC valve.

Steve

 

Thanks Steve. I will replace IAC valve and give it a go. Appreciate the advice.

 

I had the same problem. Start the enging, then watch the tach drop to zero and the engine stall. Turned out to be a bad IAC valve. Not a real big deal thankfully.

 

Try cleaning it first. No sense in spending 50 bucks when you can spend 94 cents at Wal-Mart for a can of carb cleaner. That's what I did and my truck runs pretty good.

 

if you start your engine, and unplug your iac, it should die. if it doesn't, it is bad. my book says to not clean it, but it seems like others don't always have a problem doing that. good luck, mines on the verge of going out i think.

 

I guess it is in how you clean it. I used the IAC from my 4.6 on the 5.4 that I have in the truck now. I have over 100,000 miles on the same IAC. I clean it every once and a while with either carb or throttle body cleaner. I also exercise the valve by moving it from open to closed when I clean it. I then disconnect the battery for a minute to erase the idle air trim in memory and then start the truck and let it idle for 150 minutes to relearn the it. Half of the idle time is spent with the A/C on so it can learn the idle air trim for that too.

 

It sounds like the typical IAC failure. If you get someone else to turn it over as you bang on it with a hammer, or hammer and screwdriver, and it starts then you can isolate the problem. I just dealt with the same thing on a V10 excursion. Banging on the IAC untstuck it and it works now. Cleaning it is a temporary solution in most cases, as it will require replacement in the majority of all failures