Engine stalls with a/c, sometimes red lines in neutral and runs hot



I just purchased a used 1998 Ford Fiesta with a manual transmission and 52,000 miles on it. I’ve noticed that it has the following three problems:

1.When the air conditioning is on, the engine starts hunting and the RPMs cycle between 300-1000 in idle. When driving with the air conditioning, the engine will often die at slow speeds, for example slow turns or pulling into parking spots.

2.When the engine is running high RPMs, and the car is shifted into neutral the engine will sometimes rev even higher up the red line, stay there for a few seconds and then fall back down to the normal idle speed of 800 rpm. This happens frequently when coming off a highway exit ramp and shifting into to neutral for example.

3.The temperature gauge is frequently at the very top of ?normal? operating temperatures.

Is it possible that these problems are related? Are any of them serious? Except for the air conditioning problem, I can live with them, but I don’t want to damage anything or have a more serious expensive issue later.

I bought this car very cheaply from a pretty sketchy dealer and I’m pretty sure they didn’t do any maintenance or inspections before selling it. The only thing I know how to check is the oil level. Is there any other basic maintenance I should do or things I get inspected at a mechanic? I hesitant to bring it to a garage without a list of specific things to avoid getting talked into things that aren’t necessary.

Thanks all!




1 and 2 sound like a dirty or defective idle speed control valve. Start by taking it out, clean it, and see how it does

The high temp problem could be caused by a number of things, such as a clogged radiator, bad thermostst, or air bubble in the cooling system.


They haven’t sold a Fiesta in the US in more than 20 years. Do you have a Fiesta or a Festiva?

  1. The idle air control valve is what controls the idle speed. Yours may be dirty or in need of replacement.

  2. This could be as simple as a sticking throttle mechanism. If the mechanism is dirty, clean it and make sure it works smoothly and without resistance. A frayed throttle cable, or a gas pedal that doesn’t move freely can do this, too. There are return springs on the throttle, but they are only so strong, and if something prevents the throttle from closing when you lift your foot and shift to neutral, the engine will race.

  3. Replace the thermostat. Make sure the radiator is not dirty or clogged with debris, which restricts airflow, and that the cooling fan(s) work.


You will have more expensive issues. Guaranteed. Have fun with your brakes too. These cars may be Kias. I can’t remember. Ask any Ford salesman where they are made and I bet they don’t even know.


It is a Fiesta. I live in Portugal where I bought the car. Here, the Ford Fiesta is probably the most popular car on the road - I did hear that it was sold for a while in the states, but didn’t do well.

Anyway, thanks for your advice. Everything you suggested seems simple enough, I just hope I haven’t bought a lemon… :slight_smile: