Hi - Have a '99 F150 Lariat, smaller Triton engine (4.8L) with 100K (just
turned last week), owned since new and never really had any issues and love
the truck. However, about 3 weeks ago a minor hesitation developed when
you give it gas (under load). Idols fine but hesitates when going up a
hill, accelerating, or step on it at highway speeds. (You can cruise at 65
without the hesitation, but if you give it gas it'll start). No SES light,
and wires, plugs and fuel filter are only about 15K old.
Now I did have a problem similar to this once before early last year, (15k
ago) that started with a SES light which was traced to a O2 sensor. I
replaced that but no effect, so I changed plugs - again nothing until I
changed the wires and that fixed it. The wires can't have gone bad again.
(In fact, on my Brother-in-laws's suggestion, I replaced them with original
Ford wires at $100 for the set, so they aren't some cheap after market
brand) Any other suggestions on where to look? Could it be coil/electircal
related again? Anyone know if it's a common problem for the coil packs to
go? Little short on cash so I can't afford to throw too much money at it,
so any help is appriciated!
Thanks,
Scott
monkeyboy - 11 Jul 2006 10:58 GMT
>Hi - Have a '99 F150 Lariat, smaller Triton engine (4.8L) with 100K (just
>turned last week), owned since new and never really had any issues and love
[quoted text clipped - 18 lines]
>
>Scott
First thing you want to do is get rid of that 4.8L engine, mostly because
Ford never made one. Lets go with a 4.6L. There, it's probably running better
all ready. If not check the fuel pressure. There's a service port on the fuel
rail. Looks just like the end of a valve stem on your tire. Now all you need
to do is get a gauge with a hose long enough and the proper end on it to
screw on the service port. And then drive the truck with a friend and see
what the pressure does when it hesitates. normal pressure is 30-45 psi and it
should not drop more than 5psi after engine is off.
IYM - 11 Jul 2006 11:54 GMT
I gave it an extra .2L as 100K birthday present last week.. (heh) ;)
Sorry - a little typo with that...
Thanks for the response - I'll give it a shot or have it checked....Thanks.
Scott
>>Hi - Have a '99 F150 Lariat, smaller Triton engine (4.8L) with 100K (just
>>turned last week), owned since new and never really had any issues and
[quoted text clipped - 36 lines]
> it
> should not drop more than 5psi after engine is off.
lugnut - 11 Jul 2006 15:13 GMT
>Hi - Have a '99 F150 Lariat, smaller Triton engine (4.8L) with 100K (just
>turned last week), owned since new and never really had any issues and love
[quoted text clipped - 18 lines]
>
>Scott
I would start with a freebie and clean the MAF. There are
instructions with pics several places on the web. Just run
a google search for clean Ford MAF.
This may be a good place to start:
http://www.fordf150.net/howto/clean-maf-mass-airflow-sensor.php
Lugnut
IYM - 14 Jul 2006 12:08 GMT
Thanks!
I'll give that a shot first this weekend before I start checking the fuel
pressure. Reading the info in that link you provided seems, it seems to
make a lot of sense (plus it's cheap if that's the problem) If it is the
prob, with the money I save I can afford to buy you an adult beverage of
your choice!! ;)
Scott
>>Hi - Have a '99 F150 Lariat, smaller Triton engine (4.8L) with 100K (just
>>turned last week), owned since new and never really had any issues and
[quoted text clipped - 33 lines]
>
> Lugnut