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1995 Bronco with 351. Looking for some help on this one. Engine starts up fine but won't idle or run smooth (engine lurching all over the place). The rpm's drop then go back up, sometimes it stalls. Check engine light comes on for a few minutes then goes off.
Pulled codes with a scanner and got the following:
KOEO
114 Air charge temp sensor signal voltage higher or lower than expected
116 Eng coolant temp sensor signal voltage higher or lower than expected
636 Trans oil temp sensor signal voltage higher or lower than expected

KOER
538 insufficient RPM change during dynamic response test
632 overdrive cancel switch no switch action detected

Any ideas? This seems like a lot of codes that mean nothing to me. Could the computer be going bad? Has anyone seen anything like this before?

:doh0715: Thanks.
 

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dont quote me on this but im pretty sure theres a sensor on your intake.. an oxygen or sometype of air sensor thats making it do that.. ive heard of alot of guys on here with the same prob amd thats what they said about it.. look into it.. hope i help a little.. good luck
 

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My '95 351 is doing the exact same thing. Let me tell you what I have replaced;
O2 Sensor
Spark Plugs
EGR Valve
Fuel Filter
Fuel system cleaned
and, it just spent 3 days at the dealer, $868 later, it still does it.

Let me know what you find. FYI...the first three codes you quoted are because your engine and trans are cold. Warm your engine to operating temp and then run the KOEO test, they will go away.
 

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Out of all those codes, the engine coolant temp sensor I believe is your culprit. Start with that, that should cure your problem. About $25 part. Its sending the wrong engine temp to your computer causing lean / rich fuel mixtures.
 

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Discussion Starter #7
For those of you experiencing the same symptoms mine was caused by a bad intake manifold gasket. Just had it changed with a tune up and she is running great now.
 

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Great tip. I had a similar issue with a different vehicle. It is really annoying when something so simple can take so long and cost so much to identify.
 
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