Can You Solve The Mysterious Hunting/idle Fault 96 Escort 1.8si?

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I am having major issues in relation to the idle speed when my 1996 Ford Escort 1.8 16V Si is in motion.
Whilst in a stationary position, the idle speed is in the correct position of about 750 rpm. When you are driving the vehicle and put the clutch down to change gear the rev counter needle should drop to the 750 rpm mark. However this isn’t the case and the needle is only dropping to about 1100 rpm.
If you keep the clutch down or take the car out of gear and coast, the needle remains in the 1100 rpm position. As soon as the car comes to a complete standstill and remains in the stationary position, the needle drops to the 750 rpm position.
The position of the needle when the vehicle is in motion occasionally drops to about 900 rpm and sometimes only drops down to about 1300 rpm.
I replaced the spark plugs, idle air control vale, throttle position sensor and mass air flow sensor but none of these altered the fault.
The vehicle was then tested for fault codes and the garage changed the HEGO switch crankcase, charged £175.00.
This didn’t correct the fault at all and the vehicle was inspected by Ford.
The only fault code given should that the complete HEGO switch was faulty, this was replaced and I was billed £205.00.
I took the car for a road test to discover that the fault still existed and one of the Ford technicians came along to see what I was talking about.
He then tried to fob me off with the fact that this was a normal function of the car and that the rpm will be high whilst the wheels are in motion and will only drop to 750 rpm when stationary.
It didn’t do this before and has only been doing so for two months and none of the other cars I drive do it.
The two garages will not accept that they don’t know what the fault is and I am stuck with it.
Can you help? What could the fault be if there are no codes showing following tests by Ford and the other garage?

posted by  matt77earl

no offence, but i dont think u have been driving stick shift for that long....

no matter wat the case is, even in automatics, in fact no matter wat kind of transmission it is, the higher you upshift, the higher the needle will drop to. if u shift at a point in which the car will drop back down to its idle rpm, then that just means that you are upshifting VERY early, or just extremely slow. when im driving normally, i upshift at around 3,000-3,5000rpms, and the revs drop down to around 1,800rpms-2,100. its normal in every car.

posted by  Inygknok

Well INGY, I am glad you got something from his posting because I just skimmed it as I have not time right now to re-read it and I am going WHAT??? :laughing: I have no idea what all that means...perhaps I can't read the way it is written. :banghead:

posted by  cmeseadoin

i know, i actually had to read it a few times to actually try to understand wat he meant. i actually just guessed wat he tried to imply, so i may have given a wrong answer maybe.

Let me see, I think that basically, what the guy meant was this. Okay, the car idles at 750rpm when stationary, sounds fine. The "problem" is that when he upshifts lately, the car doesn't fall back down to 750rpms, instead, they fall down to around 1,100rpms.

And I just actually read the whole thing (again) while writing this, and I think I may have mis-understood, maybe not. Apparently, while driving around, he takes the car out of gear and lets it coast in neutral. The car doesn't idle at 750rpms while coasting, but instead, it idles at a higher rpm level.

Did I understand correctly matt?

posted by  Inygknok

Your guess sounds as good as any.

posted by  tbaxleyjr

Another comment - this person spent a bunch of money on this car.

posted by  tbaxleyjr

yea..... and i think there is more money spent than wat he informed us about..... i sense a rip off mechanic :banghead:

posted by  Inygknok

OK, if you note the idle speed of your vehicle when stationary and then when you drive the vehicle and put the clutch down, the revs should be exactly the same on most vehicles (If you hold the clutch down for several seconds, or coast - only to check for faults, not for normal driving).

If this isnt the case, then there is some sort of fault.

My vehicle is showing the correct revs of 750 rpm idle speed when stationary however, the revs are only dropping between 900 rpm and 1300 rpm whilst the vehicle is in motion hence showing an idle fault.

Several weeks ago, the revs would just drop out and the car would stall but this has since been corrected.

The idle speed is also hunting whilst in a stationary position which isnt correct.

I have been given some useful advice elsewhere for possible solutions and have also had responses from others who are having the same fault. :banghead:

posted by  matt77earl

Is what I am reading is the idle speed is hunting between 750 and 1300 rpm in park as well as the other situations? Is it hunting when the engine is warm only or both warm and cold or cold only?

posted by  tbaxleyjr

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