2002 ford explorer sport trac Intermittent hard starting after driving

[Galahad]

Hi all,

Been having this issue for a few months now and I feel its getting worse and its annoying as well. I have a 2002 ford explorer sport trac with the 4.0 with 187000 miles. The issue I'm having is that after I drive my truck even for short periods at a time, park it, shut it off and go do what I need to do even if its just for a few minutes, I come back out, try to start it and it cranks up but sputters, then dies. After this happens it takes multiple cranking attempts of starting and dying before it finally fully starts, and funny thing is, after it starts you'd expect it to run rough and possibly act like it wants to die again, but once it finally fully starts, its runs fine. Its strange. I should also mention that after it sits for at least a 2 hours or more after driving it will start up on first try no issue. I do have the p0171 and secondary p0174 codes. I just want an idea of where to start with trying diagnose this problem cause I'd rather not take it to the shop and have to spend no telling how much money to fix it. I have replaced the fuel filter, PCV valve, cleaned the MAF and IAC, but still having the problem. I suspect a weak fuel pump but I just want more suggestions of what it might be before I replace that cause its pretty decent job to do and also I figured it would have completely died by now considering this has been going on for months. But anyway if anyone has any ideas of what to do or what this could be I would appreciate the help.

 

[franklin2]

I would get a fuel pressure gauge and see if the pressure is holding when you turn it off. Or are you having to pump the system back up after a stop.

 

[RonD]

Welcome to TRS

Couple of things to try
If engine doesn't start right away
Turn key off and on 3 times, this rebuilds lost fuel pressure
Then try to start


Try "clear flooded engine" mode
ALL computers have this
Key on
Press gas pedal down to the floor and hold it down all the way
(at 0RPM and Throttle sensor at Wide Open, computer will shut off injectors, to "clear a flooded engine")
Try to start, it should NOT start just crank
Count to 3 or 4 and release gas pedal, and see if it starts when fuel start to Flow again
(you can stop cranking first and then release gas pedal, works either way)

First test is to see if you are losing too much fuel pressure when it sits a few minutes
Second test is to see if an injector is leaking and flooding out warm engine

Cold engines need Rich mix, warm engine floods out

Lean or Rich codes are solely based on O2 sensors, and O2 sensors only last 12 years or 100k miles
They are the ONLY sensors that wear out
So Lean or Rich codes can only be trusted if you KNOW the age or miles on those O2s
Do you?

If not then replace them, then you can see if the codes come back, if so then you can address possible causes

 

[North Idaho 5.oh]

Every time I have encountered those codes whether it’s the 4.0 OHV or the 4.0 SOHC , it’s normally 1 or 2 things….
The intake plenum O-rings or there is a larger rubber elbow for the PCV hardline. Located to the bottom left of the intake/throttle body with 2 other hoses attached to a vacuum “tree” … that large rubber elbow likes to collapse or crack due to age and it will cause a hard start and erratic idle…. Along with a whole host of other issues/codes…