AboutDennis W Expertise I am a retired Ford master tech specializing in electrical, climate control, emissions, driveability, chassis, brakes, and any light repairs. Currently employed by an independent shop that appreciates my knowledge and abilities.
Cannot answer transmission or parts questions, these are not areas of my expertise.
Experience 32 years of auto repair, diagnosis, and emissions testing, in service staions, independent garages, and 20 years with Ford dealers.
Organizations National Street Rod Association (NSRA)
International Automotive Technicians Network (IATN)
www.blueovaltechs.com
IAMAW (retired)
National Street Rod Association
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Education/Credentials Riverside City College Automotive technology program
Ford Master Tech Certified Engine and Chassis Master (Over 500 hours)
ASE Certified in 7 categories
6 years training in Union 76 Pro-tech program
Awards and Honors 4-time Technician of the Year at Almaden Lincoln Mercury
Ford Master Tech
Union 76 Pro-tech Master tech
Question The vehicle idles varies from 500 rpm to 1000
The odb1 codes i get are 23, 31 and 84
Answer Code 23= TPS sensor out of range. Either the base idle speed has been turned up or the sensor is faulty.
Code 31= EVP out of range, not uncommon on this vehicle, usually carbon in the EGR valve holding the valve open. I always replace the sensor and EGR valve together......however:
Code 84= circuit problem in EGR vent valve, possibly a bad vent valve which could hold the EGR valve open enough to cause the idle problem.
Any or all of these could cause idle problems. Since the 23 is first, I would fix that one first and see what the results are. Remember that you will have to disconnect the battery and relearn the idle speed after repairs.
Another thing to look at is the intake plenum gasket and the throttle body gasket for vacuum leaks, which will also affect the idle. However these two will not give the codes you have.
