We have a 2003 ford explorer and it periodically doesnt start. Sometimes the engine will turn over just fine and sometimes it does nothing. We have had it to the dealer several times over the past three years and they can find nothing wrong. We have replaced the three solenoids and the Computer. We thought it was fixed this last time but it did it again today. When it does turn over it sputters and tries to start but then just doesnt. And of course when it doesnt do anything it just doesnt do anything. We have had it towed to the dealer and everytime it starts there. Any idea's?

Hi! More information would be needed to give you a better idea, such as engine size, codes that were retrieved and which solenoids you're referring to. The typical no-start Explorer concerns that I've seen have been intake air control valves (IAC) sticking, crankshaft position sensor intermittent operation, balancer concerns, fuel pumps, and non programmed keys being used to start the vehicle.

1) If the wrong key or a defective key is used, the anti theft lamp with flash quickly. When this happens, the fuel injectors are turned off and the vehicle will not start. (I don't think this is your concern since you stated that it sputters, indicating a partial start).

2) (IAC) Valve. If the IAC valve isn't working correctly, the vehicle will not start if its stuck in the closed position. It controls idle, receiving its signal from the compter (PCM). when you crank the engine, the computer contols the valve by a duty cycle, holding the valve in the open position, allowing air by the closed throttle plate. If the valve is stuck closed, no air will past the plate and the vehicle will not start. An easy test for this concern is to try to start the vehicle while holding the gas pedal 1/3 of the way down. If the vehicle starts, you have your answer. Replace the valve. It is located underneath of the plastic cover in the center of the engine (top).

3) Crankshaft position sensor. First, look and the crankshaft pulley and be sure that the belt is tracking properly. The Explorer has had issues with the harmonic balancer seperating and rubbing into the crankshaft sensor. This is usually obvious with a visual inspection. The crankshaft sensor can also have an internally open circuit that could be intermittent due to temperature changes.

4) Fuel pump. the fuel pump can cause a concern in several ways. The most common are fuel line residual pressure drain back problems or a pump not turning on. This is caused by a defective fuel pressure check valve in the fuel pump. If the check valve isn't working, the pressure will decrease and not be sufficient for the next start up. This is detected by installing a fuel gauge, running the vehicle then shutting engine off and monitoring the pressure for a drop. No more than 5 psi in an hour isn't acceptable however a problem is usually detected before this.

Another concern is an intermittent pump operation. When the key is turned on, the fuel pump is ran for approx. 3 seconds. This charges the fuel line. If the pump fails to start, the vehicle will start but sputter then stall. A weak pump will cause a start/sputter. This can also be detected using a fuel gauge. Monitor fuel pressure when starting to ensure good pressure.

Again, these are the most common explorer concerns. Other less common concerns could be chafed wiring, corrosion in wiring, and terminal pin fit at connectors, just to name a few. Good luck, no-starts that are this intermittent can be very difficult to find and frustrating to the owner. One other idea is what we call a flight recorder. It's a device that Ford dealers have and hooks into the vehicles data link connector. It has a button that the customer pushes when an intermittent concern happens. It records valuable computer information for approx. 20 seconds before and 20 seconds after the event, depending on setup. Hope you get er fixed. If for any reason you can't give four thumbs up, please ask for more information. thanks

Note the type of conditions that this happens in like high humidity,rain completely dry or does any of that make a difference? I would suspect a faulty crankshaft position sensor that is possibly cracked or corroded wires to it. If there is oil leaking onto the plug occassionally this can disrupt the signal as well.