Looking for help with this problem I have been having with my 1999 5.4.It started stalling out while driving around town,then on the freeway.Engine feels like someone pulled the plug at 70mph.I changed the air filter and it seemed to be ok for a day,then it happened again.Engine has 60,000 and has been running like a kitten,no problem's at all.Still have the same plugs,coils ,wires etc. I never ran the gas tank dry and have changed my gas filter
PS::> >Were is the IAC valve and what is it,someone told me to check it out.

THANKS

 

Pull the SuperChip and you problem will go away. I was having the same issues with mine. The Chip and the contacts need to be cleaned and the chip needs to be taped back down. It means pulling your computer to do this.

The sealed contacts that were cleaned when the chip was installed has formed a layer of oxidation between the board and the chip. This board can be cleaned with a common eraser - they will be dull before you start and shinny after you erase the oxidation away. The chip is a little different. I used a acid brush and some carbon-tet to clean them up. I don't think that the chip oxidized but I cleaned it anyway.

I installed my chip a little over 5 years ago and started having stalling and non-cranking problems in January. After a lot of frustration I tested the chip theory and pulled my chip - problem went away. I ended up pulling the computer and cleaned everything and put it all back together and everything works again. If you have had it "propperly" installed it still needs periodic maintenance.

 

Do you mean pull the super chip out and clean it or are you talking about the computer,if so were is it located.I never worked on it.
Thanks

 

could be your oxygen sensor

 

How many oxygen sensors are there,and are they easy to take out and install.I am going to clean the contacts on the computer were the super chip attaches and see what happens,if that don't work I will change oxygen sensors.
I forgot to mention that when the engine is cold in the morning and I start it up the choke kicks in and the idle is high for about a minute,then it drops way down like it it going to stall out.Then it goes way back up again,it will do this until it cut's out.If I can find the problem before it gets real bad good,if not I will take it to ford,they have the right tools to find it.
Thanks

 

You have two problems.

1) the SuperChip problem I mentioned in my other post. And yes you need to pull the computer to clean the contacts. The computer board in the truck is what needs to be cleaned to fix your shut-off problem. It is located behind the battery, held in by a 10mm nut. There is an electrical connector that plugs into a silver box (CPU). Disconnect the plug, remove the 10mm nut and you can remove the CPU.
2) Your IAC needs to be cleaned or replaced. I have 2 work trucks that have over 100K miles with the orrigional IAC - the truck I drive (99 F150 Lariat 5.4) will gunk up an IAC in 25-30K miles.

NAPA carries the IAC at 1/2 the price of the ford dealer.

 

o2 sensors will give a code

 

Tsquared I pulled it and you were right,appreciate the help.You save me a couple hundred dollars at the dealer.So take my wife instead.
Thanks Joe

 

What kind money are we talking about for a new IAC from NAPA compared to the dealer??? Mine has some of the same symptoms and it might be time to do that job. What is the consensus, clean or replace??? Since it is a pain to remove, would it make more sense to go with a new unit? Thanks...