Stop first thing you need to check is spark not fuel we know you have fuel it starts.You require correct spark to ignite fuel in combustion process.
Whats the fuel pressure?
Make sure that there is not a restriction in the exhaust system.
SOURCE: bogs from start to 1500rpm starts good runs good above1500rpms idles good
The idle speed is controlled by the PCM based upon sensor inputs using
the Idle Air Control (IAC) valve to regulate air input past the closed
throttle plate to the intake.
The PCM controls the IAC using a solenoid to move the valve body that
opens and closes the air passage to the intake. The PCM ensures a
seamless transition from IAC control to throttle plate control of
engine speed using the Throttle Position Sensor (TPS) attached to the
throttle plate.
If you pull the electrical connection from the IAC (round body fitting
bolted to throttle body) usually the engine will stall. If it doesn't
then you may have a vacuum leak. Check hoses and connections are
secure. Your symptoms are consistent with a small vacuum leak.
Try holding the idle a bit longer, then the PCM will
set a code. So that is what you need to do, try to hold the throttle
just off idle to retain the hesitation long enough for the PCM to try a
few strategies and settle on the problem and set the code. You can then
get the code read at Autozone, Pep Boys or Checker. You need the P0123
number not the description.
Hope that helps!
SOURCE: 1998 Ford F-150 4.2 V6 starts and idles fine ibut bogs when step
i had a van do this same thing to a tee turned out to be a broken key pin in the harmonic balencer causing the timing to ****** replaced balencer and ran like a dream there is a crank sensor grid on the balencer when the key pin broke it trew the timing off
SOURCE: bogs down
Even though this is an old post i feel it needs an answer since there is 225 followers wanting an answer. This situation sounds as if this vehicle is either suffering from the Throttle Position Sensor switch which has bad spots in it causing lack of voltage or the Fuel rail pressure regulator which can not keep the fuel pressure built up in the fuel rail making the auto veel like it is running out of fuel.And the transmission speed densor which also controls fuel. The situations for each device has a test that can be done to determine which one it is. And last but not least lets never forget our fuel filter this can cause the exact same problem. I am eliminating the cam sensor because it stabilizes at idle. Eliminating the crank sensor because it too at idle also stabilizes and returns a smooth idle. So a fueling problem is what we have here one of the above. Enjoy and if you need help determining which one just ask me I will help you figure it out. Please rate my advise thanks it is how i receive my achievements.
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