truck has 12k miles on it, original in every way. obvioulsly not driven much. i just bought it and have 1 issue.

the truck starts fine in the morning after the truck has sat for 14-15 hours, and even after sitting for a week.
when i drive to work i stop on the way to drop my son at daycare. the truck always restarts fine after being inside for 5 min. i drive to work and park the truck (inside garage) and it sits until 5pm. like clockwork daily th etruck will have a hard time re-starting. it will take 2-4 attempts before it will fire. the idle seems fine no surging although you can ever so slightly feel a random hickup or miss (seems like normal operation to me). no codes in the p.c and it wont trip the check engine light.
my theory is that maybe the IAC is sticking? just enough to the point where it will stick and hand open within 8 hour, but after 14 hours its enough time for it to finally shut.

thoughts ideas?

truck is 2003 with 5.4l 12k miles on ticker.

 

thanks for the help/ ideas.

 

It may be sticky or dirty injectors - put a bottle of Techron in the gas and see if that helps. Change the fuel filter.

 

I just went out over my lunch (4 hours since parked) and it had a hard time with re-start.

 

With an IAC issue, you can normally press the gas pedal and get it to start, also keep it running with some gas.

What is it doing exactly? sputtering or attempting to start, or absolutely no sign of starting until it finally does?

 

i will go to start after work and 50% of the time it will crank for 6 seconds or so until it fires and stumbles at 3-400 rpm stumbles for 1-2 seconds then goes into fast idle 1,000- 1,100 rpm's then drops like normal to 700 then 600 then runs fine. the other 50% of the time it will stumble and die after 6-7 seconds of crankin,. then it will start on 2nd crank

 

i am running some 44k through the tank now. i will drive it like normal for the week and keep track if anything changes.

a leaking injector makes me think.... so after sitting 4-8 hours the injector leaks down and pools fuel in the combustion chamber. 14+ hours is long enough for the fuel to evaporate thus not causing a hard start.

 

You can test for leaky injectors by unbolting the fuel rail. Zip tie the injectors to the fuel rail so they come up with it. Work each one until they pop out of their seats and come up with the rail. Then zip tie the rail to where it is sitting up a few inches above where it normally sits. Then put a small piece of paper, maybe brown paper under each injector. Then turn the key to the KOEO (key on engine off) and let the fuel pump prime. Check for any leaks on the paper. There should not be any fuel coming from the injectors. Make sure the injectors are zip tied nice and tight to the rail so they dont come off and squirt fuel all over. I have done this, takes about an hour and is fairly simple.

If you do have a leaky injector, you risk hydrolocking the engine. Which doesn't take much to bend a rod or flatten a bearing. So it can be a pretty catastrophic outcome if it persists for too long.

 

how much fuel could leak down through the injector when sitting? i would think no more than an once or so? i know hydolocking was a big concern on the 05+ 3v 5.4l but have yet to read about aninjector issue hydrolocking an 03 5.4l. i jsut ran down and took a sniff of the dip stick to see if fuel was washing down into the crankcase (truck has been sitting for 7 hrs). no odor of gasoline. the level is correct. i may pull the rail and do the test mentioned above this weekend when i have some time.

 

how long should i leave the fuel rail / injectors raised up with paper? i would think i would see something within an hour or so yes?

 

I think I left mine for about 20 minutes. I'm not sure exactly how much fuel it takes to hydrolock a cylinder. But I know this. Yes the 05's had injector issues that were common enough for a warranty fix by ford. But that does not mean that a pre 05 or later model cannot leak. It can happen to any vehicle. It has happened a few times from people on these forums with 2v mods. Not that common, but something to consider. And easy to test for.

While your at it and got your tools out, pull the IAC and give it a good cleaning. Make sure the plunger inside can move and isnt hung up. Then a light squirt of wd40 and put it back. I cleaned one a while back just by spraying the crap out of it. Put it back on and the symptoms were still there. Pulled it back off and lubed it a bit, then reached in with needle nose pliers and gave the plunger/valve a little tug and I could feel it was hung up. It broke free and seem to be moving nicely so I put it back. Problem gone. So make sure you clean it good.

 

do the injectors need to be plugged into the wiring loom during this test?

 

No, un clip them

 

back up to leaving work last night..

i tried to start it, it cranked for about 5 sec.. then stumbled 2-300 rpm for 2 sec and then died. on the 2nd try i held the throttle to the floor and it popped right off. it did leave a small cloud of dark smoke from the exhaust.

 

ok so last night i removed both injectors and rails from the intake and toyz recomended. i then put paper under the injectors. primed the pump by cycling the key and let it sit over night. nothing leaking on the paper. however, last night after i removed the rail / injectors i decided to see how much pressure was at the schrader valve on the pass rail. i dont have a gauge so i just depressed with a toothpick. gas just seemed to bubble out and did not seem to be under much pressure. this morning after letting the truck sit over night i pressed the schrader again just to see what it did. no gas bubbled out just a slight hiss of air..