I have a 2001 Ford Focus ZX3 (2D Hatchback) that has been randomly stalling since we bought it. There is no engine light, the dealership couldn’t get it to stall and just gave it back. Another garage got it to stall and thought it might be the “idle-oxygen sensor” (not sure if I’m remembering the name correctly), but that didn’t stop it from stalling either.
My wife is ready to dump it, but even spending a couple thousand a year on repairs is less than the grand total of a year’s payments on a new car, insurance, etc. But it would be nice to fix it. Ideas?
When you take your foot off the gas pedal, either the TPS (throttle position sensor) or a switch called by any one of several names, tells the computer. Now the computer takes over the control of the engine speed (idle) by sending signals to the IAC (idle air control) motor.
It looks like the computer is not being told to take over and control the idle, or the IAC is stuck or broken. Most of the time it is the former.
Several things can cause this, a mis-adjusted or defective TPS, broken switch that detects foot off pedal or the throttle not completely closing. The latter is usually the case.
The reason that the throttle might not be completely closing is either the throttle is dirty and needs cleaning or someone attempted to “adjust” the idle. The throttle plate had a screw that looks like an idle adjustment screw on a carburetor. What this screw really is is a throttle stop screw. It prevents the throttle body from being damaged when you take your foot off the gas suddenly.
If you suspect the throttle stop screw, back it off until it has a gap at the end, then tighten until the gap just disappears, no more.
The problem with your suggestions is that the stalling is not limited to when it’s idle. Even on the highway under constant throttle pressure, it has stalled despite tapping, letting it go, listening to see if it was responding, tapping again, etc.
If you still think the IAC or TPS is relevant, I will mention them to the new garage where I am taking it today, but if you have any other ideas, I welcome them. For another bit of information, the stall sounds and feels as though it is running out of gas.
That’s new information, it does change things. Now it actually gets more difficult because that can be extremely difficult to troubleshoot. You have to catch the fault as it happens.
The ignition switch would be the primary suspect for this, but I cannot guarantee that it is the problem.
Have you experienced this at night? If so, did you lose headlights when it happened? Do you loose other accessories like AC, radio?
When it stalls, does it ever restart on its own? If not, can it be restarted right away? If you have to restart it using the starter motor, do you have to pull over or can you slip it into neutral or push in the clutch (auto or manual?) and restart on the fly?
Do you have to wait for any period of time before restart?
When it stalls, does it just quit, or does it hesitate and/or stumble first and then quit?
Have you experienced this at night? Can’t remember it happening at night and I am uncertain about the accessories, but I think they remain on.
When it stalls does it ever restart on it’s own? Yes, sometimes it doesn’t actually stall completely but just runs very roughly for a 10-20 seconds and then smooths back out. But normally, once the sputtering starts, the engine does die.
If I have to restart it, do I have to pull over or can I clutch start it? It is manual, but I’ve never tried that. If the sputtering doesn’t smooth out, but dies, then I just pull over, shut everything off and then restart it.
Do I have to wait a period of time before restarting? I would say no. It might not start with the first key turn, but the success rate of starting the engine after stalling is no worse than the success rate of starting the engine when it hasn’t been running.
When it stalls, does it just quit or hesitate and/or stumble first? It ALWAYS stumbles. In fact, once in a while it will smooth back out and keep on running (normally not). But it sounds like it’s either missing very badly, or running out of gas, a VERY rough sputtering and then it either dies (usually) or sometimes smooths out and keeps on running.
