Hey guys and gals!
I sure could use some help with my truck. I'm pretty much at a loss and to be fair, I'm not mechanical. I know enough to be dangerous, but I'm very hands off. I sure could use some guidance.
My truck is a 2003 XLT with the 5.4L Triton. It also has 198K miles on it.
The issues seem to be multiple but I have no idea if they are related or what's going on but nothing is consistent and I cannot get the issues to repeat in a consistent manner as sometimes things happens, sometimes they don't and it's never at the same time. The issues are as follows:
Sometimes after starting, backing out of the driveway and beginning to move forward, the engine seems to sputter and misfire as if it's not getting fuel. This doesn't last very long before it seems like power is restored and the engine is running on all cylinders, and sometimes it's as if there's a surge before things smooth out. Other times, it seems to misfire a little bit while driving, with a loss of power before it smooths out and just purrs down the road. There are also times when I will stop at a stop sign and the engine acts as if it's going to stall. It has thrown the service engine soon light on a couple of times, but then the light can disappear and not be on.

What has been done to this so far is:
Replaced an ignition coil and sparkplug on a cylinder which was throwing a misfire code.
Fuel injector cleaner was poured into it.
Replaced the IAC valve.
Mechanic has also tested the fuel pump which he said tested at 38 psi.

I'm very tired of this and just want my truck to run. Any suggestions?

 

Did he test the fuel pressure regulator ?

When was the fuel filter last changed ?

 

I thought he did.
I'll have him check those out too. This chasing a ghost thing is driving me nuts.

One of my friends said he had a vehicle doing the same thing and it turned out to be a cracked plastic electrical connector which had some moisture in it. I know just enough to be dangerous but otherwise I'm pretty useless when it comes to mechanical stuff.

 

I would change the fuel filter as that is pretty simple and cheap. It sounds like a fuel delivery problem. If the filter does no good, perhaps the pump pickup sock is clogged in the tank. I would think a code reader would be giving you some info even if the light is not staying on.

 

This just happened as I was bringing my dog in from the dog park.
I'm braking to stop and the engine is sputtering, acting like it's going to stall. With my foot on the brake stopping, it surges and seems to accelerate as if I'm pressing on the accelerator.

So, with what you guys have said, I'm leaning towards fuel system?

 

That sounds like a vacuum issue.

You need to pull codes! They will still be present with the CEL turned off. Until then, we are noncommittal on a diagnosis.