I have a 1997 F-150 4.6L that recently started to stall when idling this has occurred intermittenly.
The first time my truck stalled the engine started to rock very subtly while accelerating once I started to brake for a the light it rocked some more and died.
It then started up the next day after being towed, the second time this happened was when
I stopped going up a hill the engine rocked slightly and died and the truck started right up the next day.

Each time this has happened the check engine light has not come on and when read there are no errors. I highly doubt that its the fuel pump I just had it replaced two years ago.
So far I have had two mechanics look at the truck and the only conclusion they can come to is that ECU has gone bad.
Any other thoughts would be appreciated.

 

I'd suspect the IAC before I would the ECU. It's easy enough to pull and clean or replace.

 

It has been surging when I start it up in the mornings and I see that is one of the symptoms of a dirty IAC

 

Check the fuel pressure just to rule it out.

 

I should have put that info in my initial post both mechanics have checked the fuel pressure and they said it was good. Someone also told me to check my oil filter I just changed my oil two weeks ago? Would this have any significance as to why my engine dies?

 

I also did change the oil filter but a friend said that the oil filter could be bad?

 

I'm really surprised that neither "mechanic" looked at the IAC.

Oil filter has nothing to do with it as long as your oil pressure gauge is reading normal.

 

Has the fuel filter been changed? It wouldn't hurt to change it just to be on the safe side if it hasn't been done in a while. It does act like an IAC valve as glc stated though. You shouldn't have to have it towed for an IAC problem, just press the throttle a little and it should start, if not I would suspicion something else.

 

Well I replaced the IAC today and now the truck does not start

 

JCR 56: Fuel filter has not been changed that will be the next thing I look at.
The IAC had a lot of corrosion so I replaced that today however truck no longer starts.
I have current to the IAC connection and everything is hooked up.
The first time it stalled I had to have it towed because it refused to start.

 

Will it start if you press the pedal down a bit? You may want to pull the whole throttle body and clean it. The EGR passages in the elbow love to plug up, a good time to clean those out anyway.

 

I pressed the pedal all the way down nothing happens

 

Don't press the pedal all the way down, just press it down a little, if it doesn't start then it's something besides the IAC.

 

It won't start if you press it all the way down, that shuts the fuel injectors off.

 

Just to give an update, realized my fuel pump wasn't engaging and had it replaced, wasn't more than two years old.
Truck now starts but I am having other problems which I have posted here https://www.f150online.com/forums/tr...ml#post5184529