The trucks idle fluctuates in park only...

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The trucks idle fluctuates in park only...

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The trucks idle fluctuates in park only... - 3/28/2008 4:55:41 AM

jmack91z28

Posts: 164
Joined: 2/27/2008
Status: offline

I've got a 94 2500 4x4 with a TBI 454 with 137k miles, when the tranny is in park the idle jumps up and down about 75 to 100 rpms, but it doesn't act up at all in drive or any other gear. The fluctuation isn't real bad but just enough to get your attention, anybody have a guess at what it might could be? I've only owned the truck for 3 months so serivce records and repairs I don't know. To my knowledge only the fuel pump and alternator have ever been changed and the motor is completely stock. The guy before me did put in a 7-wire brake controller himself and the wiring job is pretty ****ty, but that shouldn't affect anything, I wouldn't think. Thanks

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RE: The trucks idle fluctuates in park only... - 3/28/2008 6:38:51 AM

northey87

Posts: 927
Joined: 10/17/2007
Status: online

Its do to the truck being in park, in park the engine is free to spin without resistance. While in gear the resistance from the trans helps stop the engine rpms from bouncing.

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''''95 1500 Silverado, 350, flowmaster Force II exhuast, S&B CAI.

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RE: The trucks idle fluctuates in park only... - 3/28/2008 7:58:06 AM

jmack91z28

Posts: 164
Joined: 2/27/2008
Status: offline

Well it doesn't always do it, just most of the time, and i've never noticed any of my other vehicles doing it before. But I am known to over analyze my vehicles and think there's something wrong when there really isn't.

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RE: The trucks idle fluctuates in park only... - 3/28/2008 8:06:23 AM

northey87

Posts: 927
Joined: 10/17/2007
Status: online

Try turning off your ac/heater and see if it still does it, its probably the ac compressor that causes the flucuation every time it kick on and off.

_____________________________

''''95 1500 Silverado, 350, flowmaster Force II exhuast, S&B CAI.

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RE: The trucks idle fluctuates in park only... - 3/28/2008 8:11:21 AM

jmack91z28

Posts: 164
Joined: 2/27/2008
Status: offline

The heater isn't on and the a/c doesn't work. The guy before me broke a line loose so there's not freon in the system, and the compressor does make a squeaking noise when the motor is running.

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RE: The trucks idle fluctuates in park only... - 3/28/2008 8:27:40 AM

northey87

Posts: 927
Joined: 10/17/2007
Status: online

No matter its probably normal, If I remember right, my parents '95 3500 with a 454 did the same thing.

_____________________________

''''95 1500 Silverado, 350, flowmaster Force II exhuast, S&B CAI.

(in reply to jmack91z28)

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RE: The trucks idle fluctuates in park only... - 3/28/2008 8:36:57 AM

jmack91z28

Posts: 164
Joined: 2/27/2008
Status: offline

Well I hope you are right. I know what your talking about now with the compressor switching on and off. It's not like that though, it happens probally every 5 seconds. My first thought was its no big deal, it's just normal, but I wanted a couple of other opinions just because. And like I said, it's not a big drop, really nothing to be concerned with, but you never know..

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RE: The trucks idle fluctuates in park only... - 3/28/2008 10:26:46 PM

Coppertop71

Posts: 35
Joined: 12/3/2007
Status: offline

There could be a vacuum leak causing your Idle air solenoid to fluctuate or the vcauum leak itself could be a cause. You could check it by spraying some carb cleaner around some hoses, intake, and throttle body. I dont have much experience with these engine components but for Jeeps a dirty IAC needle is a common, to fix it you just remove it and clean the pin assembly and housing inside the throttle body. On the Jeep you have to use caution not to try and turn the pin, I imagine its the same on these chevy's.

_____________________________

''''06 Silveraldo 1500, 4.8L 2X4 (Hers)
''''01 Silveraldo 1500, 5.3L 4X4 (His)
Coppertop71 @ jeepforum.com

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