idle problem back
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idle problem back
2000 ranger 2.5 245000 miles. code po171 and idle problem has come back. replace ICV, EGR, MAF, PVC, check fuel pres, air cleaner, plugs, wires, O2, check for vac leaks, Intermintenly coasting at 20mph out of gear (stick shift) engine revs to 2500 rpm and holds until i brake to a stop then it idles down. So I disconnect the ICV and it runs perfect. (its a new ICV) something is telling the ICV to open up. a month ago it did the same thing when i replaced the EGR the idle problem cleared up so I thought that was it. There is a relationship between the truck speed and the engine speed but how does the engine speed know the truck is moving when its out of gear. It work perfect for a month all of a sudden it starts this problem again. Im thinking of taking it to the ford dealer for a dianostic test but i dont know how spisific they can get on whats wrong I dont what to them to just say "oh you have a vac leak" . . . I know a 171 could be vac leak but the problem is so darmatic and off again on again it seems more like a part problem then a vac hose is either leaking or not.
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Joined: Jan 2004
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From: SW Va
You've been busy on this one & may have more than one problem.
After all the part replacements, did you disconnect the battery B- cable for say 5-10 minutes, to wipe the computers corrupt fuel trim KAM, then perform the cold & warm idle relearn routine????
The rear differential mounted speed sensor tells the computer how fast the vehicle is moving.
The P0171 code is for the upstream O2 sensor, saying its not switching & is at its adaptive limit/stuck lean. So since the O2 sensor has been replaced, this might suggest a fueling control problem, so post your +/- short & long term fuel trim numbers, KOEO & KOER fuel pressure & MAF sensor numbers.
Post All trouble code Numbers you have, as they can provide good trouble shooting clues.
If you have a vacuum gauge, have a look at & post your engine vacuum reading at idle & about 2K rpm & note if the vacuum reading is steady, or wandering around.
Why did you replace the EGR valve, was it all rusted up & throwing trouble codes????
After all the part replacements, did you disconnect the battery B- cable for say 5-10 minutes, to wipe the computers corrupt fuel trim KAM, then perform the cold & warm idle relearn routine????
The rear differential mounted speed sensor tells the computer how fast the vehicle is moving.
The P0171 code is for the upstream O2 sensor, saying its not switching & is at its adaptive limit/stuck lean. So since the O2 sensor has been replaced, this might suggest a fueling control problem, so post your +/- short & long term fuel trim numbers, KOEO & KOER fuel pressure & MAF sensor numbers.
Post All trouble code Numbers you have, as they can provide good trouble shooting clues.
If you have a vacuum gauge, have a look at & post your engine vacuum reading at idle & about 2K rpm & note if the vacuum reading is steady, or wandering around.
Why did you replace the EGR valve, was it all rusted up & throwing trouble codes????
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