For the past 8 years when ever I pull my boat (2800 lbs) on vacation on north 94 in Minnesota in July heat, the check engine light MAY come on (no heat troubles). But what frost's my $#! is that when we stop for lunch, on the off ramp it sputters and dies, or it has no power. Last time JUly 11-15 2005 , it missed - backfired (first time for that) but did not die, no check engine light.
97k on 1997 4.2.
Replaced plugs and wires 30-40k ago, no change at that time.
Thoughts? I have searched the files but would cleaning MAF help?
Original fuel pump, regulator o2 sensors.
Would the Auto Zone check show me anything?
Help?
Thanks for listening,
Jeff in MINN

 

could be vapor lock

gas is boiling in the rail = stalling, no power as you describe

...zap!

 

Why would it be worse now, later in years? I have not gone Auto Zone to any codes pulled yet, but I would like an idea of what to expect could be wrong. I have not replaced a thing with the emmisions system at all.

 

Is there a way to insulate the fuel rail? 90's here in Mpls soon and now even just driving around town with the air on it's acting up.

 

Vapor lock on a two pipe fuel system? Don't think so!
Insulating fuel rails? Don't think so!
Find and fix the problem instead of guessing.

 

Best advise ever! LOL

I think if he knew what the problem is, he wouldn't be guessing

 

Vapor lock can't happen on a modern two-rail system. The fuel is always circulating from the tank to the fuel rail, through the pressure regulator, and back to the tank. That's why stories of vapor lock on our 97-03s is such a laugh.

Without some more troubleshooting, it could be a lot of things.... I would suspect a transmission problem, specifically the torque converter failing to unlock as you slw down. When was the last time you had the trans filter and fluid changed? It could be that simple.....

-Joe

 

Thanks GIjoe, I have had the tranny flushed regularly (30-40k) and it doesn't just die at the end of the ramp, I come to a stop first and the in 5-15 seconds it stumbles and dies. This year it only stumbled, I have gotten good at "feeling" it ready to happen, put in neutural, rev motor and no problem. I thought vapor lock was thing of the past also. Is cleaning the MAF sensor something that should be done? If so, how to do?
Again, NO check engine light on this trip. Heat is on all across the USA any one else having this problem. Long run V6 dies and end of road?
This has been a great truck!
Thanks, Jeff

 

You may need to get a graphing scan tool to find out something like this. My truck was doing the same thing for 4 years-two ford dealers could not figure it out. It turned out to be bank 1 o2 sensor failing when really hot-I replaced them both and no more troubles. Not one check engine light came on when it was stumbling and stalling.

.....john

 

When it starts to happen, does shifting into neutral alone help it, or do you need to rev it to keep it from stalling?

-Joe

 

Shifting will raise the rpm enough to keep it from stalling, but it still idles low. Just yesterday I came off the freeway, seemed fine 2nd stop light low power. I keep thinking lower fuel pressure at that point or some thing.

 

my truck was was doing the same thing after it would get warmed up. When I would stop at a stop light it would stumble and act like was going to die. I pulled the codes and they came back as as the bank 1 up stream oxygen sensor. After I replaced that I haven't had any problems since.

 

I'm going to stop at Auto Zone and pull codes.
Thanks for all your input.

 

Had a problem like you with my 1998 5.4 XLT. It only when trailering my 24 ft travel tailer pulling into the toll booths intermitantly. It was one of the O2 sensors. In checking with several auto authorities and the web it is recommended that all heated O2 sensor be changed @100k miles. Just like plugs they have a life expectancy. I changed all 4 and my 5.4 has never been happier.

 

Did you use Ford O2 sensors or others.
I replaced my sister with Bosch I believe, and one only lasted 10 months.