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Ford Escort Rough Idle In Gear

Q. The car runs great except for a rough idle when stopped in gear. The idle seems fine to me while in neutral. I also have hard starts sometimes. But it is the rough idle that is driving me nuts. By using a multimeter for testing I get the following trouble codes:

Ford Escort Rough Idle In Gear

KOEO #33
I think this code means EGR valve opening not detected.

This does not make since to me, the EGR open or partially open should give me a rough idle (my symptom), being closed is what I want at idle, right? Could this still be an EGR problem even though the error code and the symptom seem to be at odds? I did put a vacuum on the EGR and it acted like it was supposed to and did a very rough idle and would have killed the engine if I had kept the vacuum on longer.

#133
Do not know what this code is?

KOER #2
Engine identification code (½ # of cylinders) which is correct.

No other error codes. I did test again while the air conditioning was on to simulate being under load like when it is when in gear and got the following codes.

If tested with air conditioning on I get the following two codes.

#411
Cannot control RPM during KOER low RPM.

#412
Cannot control RPM during KOER high RPM.

#539
A/C on during test.

I tried to run the tests while in gear but could not get the test to run. I checked the voltages on the IAC valve and they were OK, there is a note on the valve saying not to clean it inside because of special surface coating. I don’t know what to do????

  • 1994 Ford Escort Wagon
  • 1.9 liter SEFI
  • VIN# 1FARP15J0RW218952

A. I think DTCs 2, 33 and 133 are not relevant as far as the idle problem is concerned. In fact, I have no listing of those DTCs on my charts which may indicate a bad PCM.

Ford introduced three digit EEC-IV Self-Test codes in 1991 to accommodate the increasing number of service codes required to support various government On-Board Diagnostic (OBD) regulations. The phase in from two digit to three digit codes started in the 1991 model year and was largely completed by 1994 except for some medium/heavy trucks that will retain two digit codes through the 1994 model year.

DTC 411 and 412 indicate a bad Idle Air Control valve (IAC). I would try removing the IAC solenoid and inspect it for contamination. If contamination is present, determine if the solenoid is a type that can be cleaned.

Ford Escort Rough Idle In Gear

This type of IAC solenoid (above) is serviceable and may be removed and cleaned of sludge deposits that accumulate within the valve.

Ford Escort Rough Idle In Gear

This type of IAC solenoid (above) is not serviceable and cannot be cleaned

If it can't be cleaned, or cleaning is not effective, I would try replacing it. Of course I'm assuming that there are no vacuum leaks present.

  • KOEO refers to Key On Engine Off (KOEO)
  • KOER refers to Key On Engine Running (KOER)
  • DTC refers to Diagnostic Trouble Code (DTC)
© 2003 Vincent T. Ciulla

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