There can be a misfire too from the cylinders.
An engine that
hesitates, stumbles or misfires when accelerating or when
it is under load is an engine that is either sucking too much air, not
getting enough fuel or misfiring. If the Check Engine Light comes on,
you may find any of the following codes:
• P0171, P0174 Lean
fuel condition codes
• P0120 to P0124 Throttle position sensor codes
•
P0222 to P0229 Throttle position sensor codes
• P0400 to P0409 EGR
related codes
If there are no misfire codes, a common cause of
acceleration stumble is a bad throttle position sensor (TPS). The TPS
tells the computer how far the throttle is open. The computer uses this
information to determine how much fuel is needed to maintain the correct
air/fuel mixture and when extra fuel is needed if the throttle suddenly
opens wide.
Another common cause is dirty fuel injectors. If
varnish deposits have built up in the tips of the injectors, they won’t
spray as much fuel as they normally do, or will “dribble” fuel instead
of spraying a fine mist. This creates a lean fuel mixture and
conditions that are ripe for stumble and hesitation (also misfire). Look
at short term fuel trim (STFT) and long term fuel trim (LTFT) with your
scantool.
If the numbers are high, it tells you the engine is running lean and
the injectors need cleaning. Treat mild cases with a high quality
fuel-injector cleaner additive. Severe cases require professional
cleaning equipment.
Also if this sensors apply to your
vehicle, camshaft sensor or
crankshaft sensor if sensors bad you don't get any spark. Also
run a scan on the car.
Good
luck and rate this solution,
please.
Check your error codes first! use a code reader then: if you can't assertain the problem:
check the timing flashes to see if your ignition is steady using a timing light (this can be done while you drive if you place the front of the timing light under your windshield wiper (lens facing you.)
if timing is good check fuel pump pressure by attaching a gauge to the fuel rail good pressure? (usual problem is the fuel pump filter in the fuel tank) or, ignition module getting too hot (the ignition can be checked by: running the car in neutral and, applying a heat source: i.e. hairdryer to the ignition module.) this won't hurt the module.
let me know what you find.
JG
Look you need to have the fuel pressure monitored when this loss of power occurs, so have a shop hook up a special test unit and drive it to see if the fuel pump looses pressure, that may be the problem.
yes this would stop it from restarting, u need these tests run to pin the problem down, i have been doing this type of work for 35 years, i am a factory trained technician with a master certification, if there was a magic fix I would have found it by now, so have the tests run, fuel pressure and fault code testing. Trust me on this I do know what i am doing here.
nothing appears on the scan
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Have your fuel pump pressure tested!
Your car could be running great because its demand for fuel pressure is met at idle. But at part and wide open throttle you fuel pump could be running aground.
A mechanic with a fuel pressure gauge can drive the car around and see if the pressure falls flat during off idle throttling.
Good luck and be careful!
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There is no dealer within 100 miles of here and I cannot get it there because when I dive it for about a half block it staves out of fuel. would you suggest replacing the fuel pump or does it sound more like som sort of sensor
I have an 1999 Infinity QX4 4WD. It started missing so I changed the plugs, plug wires, distributor cap, rotor, and fuel and air filters. It won't start. After it cools down it will start and run fine for a long period of time idling. but when you go to drive it after a half block it seems to starve out of fuel. There is no dealer within 100 miles and I can't get it there. Do you think I should replace the fuel pump or does it sound more like a sensor?
would this stop it from restarting after shutting off? The problem is where I live and I have no way to get it to a mechanic so I am trying myself
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