I have a Ford Focus 2001 Ghia Hatchback 5 doors, 1.6 Petrol, GHIA.

From time to time it likes to die when I try to give it gas.

The Main Problem

Symptoms:

Once the car is warmed up it can no longer go above 5000 RPM in 2nd gear. Let’s call this occurrence – Rev Choke, and the RPM it occurs at – Choke RPM.

When Rev Choke happens, the car would start going back down to ~4900 RPM, then going back up to 5000 RPM. In an endless cycle. There’s a slight judder that can be felt every time it does that.

If I drive the car while it’s warm for long enough, there’s a chance the Rev Choke would suddenly start occurring at lower and lower RPM. If that happens, in the span of 5 minutes it would go from its previous 5000 Choke RPM, to 4000, 3000, 2000…

Like noted above, when it first warms up, the choke is at 5000 RPM. The more I drive it (after it’s warmed up), the bigger the chance it would hit a point where the Rev Choke would suddenly begin to occur at lower and lower RPM.

I can rev slightly above the Choke RPM if I slowly depress the accelerator by about 20%. If I go above those 20% the car suddenly cuts off and tries to die if I don’t go back to these 20%.

If I drive for too long when the problem has occurred, it comes to a point where giving it any throttle would cause the car to judder and actually lower the RPMs instead of rising them. If it were at 1000 RPM Idle, it would instantly go down and try to die. If I do that, and then let go of the accelerator, the REVs will jump to 1200 RPM and then come back to 1000 (idle) and stabilize.

The car is stable and can stay at idle RPM, even when the problem is at it’s worst.

Causes and info:

  • Happens only when the car is warmed up.
  • The longer I drive, the bigger the chance it would occur.
  • Does not happen every time.
  • Usually noticed only during hot weather.
  • Putting the AC on cold and letting it run would increase the chance that the problem will occur.
  • Also, the engine loses a notable amount of power when the AC is on.
  • In cold weather it’s much more rare, but it would cut off instantly without any warning, acting like it’s out of fuel.
  • One time I entered an underground garage, and later when I exited the car completely shut off and had to be towed to a gas stop, even though the tank was half full.
  • Even when the Rev Choke happens and I kill the car by giving it too much throttle, it would instantly start back up.

What helped:

  • Adding more fuel to the tank will completely eliminate the problem for a good amount of time. Except last time a Rev Choke happened, I had a full tank and couldn’t add any more fuel.
  • Giving the car a 5-minute rest will cause it to run semi-well for 5 minutes afterwards, but coming to a juddering stop afterwards.

Different diagnosis given by different mechanics:

  • Spark plugs
  • Filters
  • Timing belt
  • Pump
  • Losing electrical ground
  • Bad chip
  • Bad fuel pressure regulator

What I’ve replaced:

  • Spark plugs
  • All filters, except the one in the tank, mounted on the petrol pump.
  • Timing belt
  • Radiator fans.
  • Cylinder temperature sensor.

I still don’t have a fix for this problem. I will be changing pump soon.