Idle issue and i pulled some codes

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Mar 28, 2010 | 08:11 PM

twister2gt

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Idle issue and i pulled some codes

89 F250 351W C6 trans. For the most part the truck runs fine but every now and again when i'm in gear at a stop light it will start idling really rough.

34 EVAP Control system Fault/Voltage higher than closed limit

34

34

41 HEGO (hO2s Sensor Signal out of range/always lean

34

41

this is how the codes came out twice on my code reader, it was 34 34 as hard codes and 34,41,34,41 as continuios memory codes and i checked it twice just to make sure. was wondering if anybody can point me in the right direction to fix these. When i got the truck it didn't have a O2 sensor but i installed one and it doesnt have cats and the smog pump isn't hooked up

Mar 28, 2010 | 10:25 PM

twister2gt

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bump..............

Mar 28, 2010 | 10:48 PM

MAS96F150

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From: Mt. Clemens Michigan

o2 always lean would lead me to believe that the o2 sensor is either faulty or the wiring could be shorted/open somewhere. i dont think that the evap would make it run rough at idle or not. but sounds like the control valve windings are open if fred is seeing high voltage.

Mar 28, 2010 | 10:50 PM

MAS96F150

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but since the o2 is not a hard fault the truck could just be runnin lean, vacc leak or low fuel pressure could also be an issue

Mar 29, 2010 | 07:30 AM

twister2gt

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how long do the stored codes last because i did replace the o2 sensor about 6 months ago

Mar 29, 2010 | 09:58 AM

jjarboe01

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unhook your battery for a while so the computer resets and relearns the sensors. It likely has not relearned that you have a new O2 sensor on the truck, go from there.

Mar 30, 2010 | 07:01 PM

twister2gt

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Okay i reset the computer today found a vac leak on the transmission shift modulator fixed that and fixed a couple vac lines under the hood that were capped off, now the problem is worse then it was before there is one vac line that i couldn't find were it goes, it is one of the red nylon ones going in the direction of the green one that goes to the EGR valve. I checked the codes and only got code number 34 again. It misses really bad when just idling but it doesnt miss when your driving it is is really smooth running from 1000 on. I was wondering if anybody has a picture of the that vac line group that go to the plastic box on the pass side next to the alternator?