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Ford Ranger question! Help!

I’ve got a 2000 Ford Ranger, manual 4 cyl. When cold, she’s been stalling out. It happens very reliably when I come to a stop and put it in neutral (or put the clutch in). Only when she gets warmed up does it stop. Check engine light has been on (for a long time) saying the TPS sensor is out and the 4 cyl. is misfiring. I replaced the TPS sensor and it had no effect on the problem. Any ideas? A friend recommended changing the oxygen sensor. Any help would be appreciated!

Clean the throttle and the idle air control valve. When started cold the engine should rev to 1500+ RPMs and gradually drop to about 900. If that doesn’t occur the idle air control valve may not be functioning. Also, the EGR valve could be leaking. And, BTE, what brand plugs did you install?

There is no code that says “TPS sensor is out.” You will find quite a few codes that reference the TPS circuit. Many people make the assumption that this means the “part” is bad. But the “part” is only one piece of the entire circuit. So post the actual code if you want people to help. But check out the entire TPS circuit.

As for the Cyl 4 misfire - I have to assume that is a P0304 code. For that you always just start with plugs & wires. From there its best to move to compression check before you blow a lot of time & money on nothing.

Whatever you do don’t listen to friends who suggest that you start throwing parts at it based on random guesses.

It’s not the oxygen sensor. The O2 sensor doesn’t come into play until the engine is at operating temperature. So if the problem occurs when the engine is cold, the O2 sensor isn’t the problem.


The specific code for the TPS is P0122. Not sure what brand the plugs are… but they were put in 3 years, 40,000 miles ago. The misfire has been happening since I bought the truck though.

First, make sure that code is still there. If so then check this out:

The last thing you do is replace the TPS after you’ve checked its mounting & adjustment and wiring. Some TPSs do need to be adjusted (i.e. you don’t just bolt them on & go) - I don’t know whether this one does or not. Autozone has free online repair info for many vehicles - you just need to register and email address &plug in the truck’s info. It should tell you whether the TPS needs adjustment & if so how. It will also give you the basics on testing.

As for the misfire, I would inspects the plugs & wires, swap the number 4 plug & wire with another and see whether the misfire moves. I’d also be checking the compression.