I have a 1999 f-159 Triton 4.6 engine it wont keep running unless my foots in the throttle if im moving its OK only when i come to a stop problem happens i went and got spark plugs no my problem is no plugs under manifolds r they the 8 thing on top of engine 4 on each side with plug and wires to each one

sounds like a bad throttle solenoid. when you shut off the car, the solenoid allows the throttle to close completely to keep the engine from dieseling when shut down.

Hi Wendi:
If the engine runs fine except when you don't have your foot on the gas, maybe the idle stop needs to be adjusted. With the engine off, have someone step on the gas pedal while you look at the linkage at the carb. There should be a plate with a screw in it that keeps the butterfly valve from closing completely. This can be adjusted with the engine running. (SAFETY FIRST - MOVING PARTS CAN BITE)
If the engine will only run at not nice too high RPM, chances are that the idle jet in the carb is plugged, and a carb cleaning and possibly overhaul may be needed.

It will probably be OK. But if you can, find a can of brake cleaner and a toothbrush. Remove the air plenum from the throttle body. Use the cleaner to clean the throttle body inside and the back of the throttle plate as best you can. Especially around where the throttle plate sits. It will take a second or two to restart the car. Once started spray some of the brake clean into the throttle, rev it up to keep in running. This will help stop the dieing out.

hot or cold engine,or both????????????????????
sure...
the ECU works OVERTIME; hard, to keep the engine running.
this is done by the action of the ISC valve.
so can you keep it running with a fast right foot??????????
a real mech needs to drive car.
does it have full power on hills?
is the tune up service done, the 60kmile repeats and needs to be done.
the ECU can not keep idle right on any engine that runs like crappppppp.

1: all fuses good.
2: engine never warms to normal 180F+ temp and hold???
3: not tuned up.
4: engine misfiring.
5: engine flooding.
6: engine starving for fuel.
7: OMG, the ISC wires fell off, (inspections do work on old cars)

there are simple tests. for each case.
one more #8. EFI system lost 12vdc power. stalls.
12.6vdc not running, 13.3v -15v running.

Could be a dirty throttle body, or a stuck idle air control valve.
Is the check engine light staying on now ?

Check the oil. Quite a few cars do that when they are low.

try and clean the throttle body and throttle plate and the idle air contol valve

Could be that your TPS (throttle positon sensor) is going out.

Suspect idle air control valve. Also clean the throttle body. If its gummed up dirty it will restrict air.

Check the compression using a compression tester you can buy at a parts store. The compression has to be fairly high in all cylinders to start up the engine. If not you may have bad rings . Check plugs and wires too.