I have an 03 F 150 with the 5.4. Occasionally when going to start it it will crank but not start until I hit the gas. It also has a rough idle. When I hook up my scanner it shows no DTC's.

My first thought would be the IAC, should that throw a code? I cleaned it, still did it earlier today.

So basically what I am asking is will a bad IAC cause a no start?
If I should replace it, is there any brand that is better than the others (Napa,carquest, etc..), or should I stick with motorcraft?

Thanks!

 

If it starts when you crack the throttle open, it's probably the IAC. The rough idle kinda confirms that. If cleaning it didn't help, I'd probably replace it, and pull the TB and clean that too.

For reference, a Motorcraft is $68.79 at Rock Auto. Aftermarkets are in the $45 to $60 range. A Duralast at Autozone is $52.