Hi, I have a 2006 f150 4.6L that is having a peculiar problem. When I start the truck up it does not want to start "normally" but rather sputters some (will sometimes stall) for about 5 seconds, but then it runs perfect with no other symptoms or noises. (rough startup on tach: https://photos.app.goo.gl/4wwbiXwTS901Etys1) (normal startup: https://photos.google.com/photo/AF1Q...H3U4WMFVYQwyxv). I've thought of a couple diffrent things it could be: Some sort of sensor (MAF, o2?), sparkplugs, fuel filter. What are your thoughts on this before I spend any cold hard cash?

 

In order to hear the engine, you have to turn the radio down.......

Rough start followed by smooth running is usually leaking injectors. In this case, cold starts will be OK but warm starts after its been sitting a few minutes is where the symptoms will be the worst.

 

I Really just wanted to show the tachometer as the engine sounds normal except the low revs. It is also the opposite of what you said as it will start rough cold, but after running a few minutes it won't happen.

 

New not reman they can cause serious engine damage if leaking . They are subject to heavy wear . And yes they are expensive .

 

Try turning the key to "run" and then waiting about 3 seconds before starting to see if the situation improves. I still think it's a fuel delivery issue, and still possibly injectors leaking down.

 

 

Not necessarily , I had leaky injectors and it started great cold but had warm start issues and went away after new injectors. Might be your fuel pump or something else however I'm no expert on injectors. i know in my case when they leaked after stopping and letting it sit all night the extra gas didn't do anything on a cold start but once warm cranked weird, started weird and so on. Someone can chime in

 

What Tommy said was also my experience with dripping injectors, as I mentioned earlier. Cold starts were unaffected, but warm starts would sometimes stumble and die due to the engine being semi-flooded. That being said, to check them you need to pull the injectors with the rails attached and then turn on the key and physically look for any that drip. If you have to disconnect any injectors from the rail be careful and wrap the first one with a towl, because you'll get a fair amount of fuel expulsion under pressure.