Strange Idle...
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Senior User
Joined: Sep 2008
Posts: 312
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From: Huntsville, Tx
Strange Idle...
Was sittin in my truck this morning waiting for class, must have been sitting there idling for about 30 minuets or so, and began to notice every so often the truck would start to shake a little more the usual and it would clear up. it seems to idle about 600rpm and when it would start to shake it would drop about 50rpm. Decided to check it out stepped on the throttle and brought it up to 1000rpm held it and for about 30seconds it stayed and then it dropped to 750-800 rpm for not more then 5sec and went back up to a 1000, and then repeated the cycle. Is this normal, or is there something wrong? Truck seems to run just fine on the road and i havent noticed it even with the cruise set. Just wondering if there is something i need to be looking for or it is just the nature of the beast. Also my programmer is set to "tow-safe" and havent taken it off yet.
Posting Guru
Joined: Mar 2009
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Every now and then I have the same problem so ill just shut it off then retsart and it will go away then come back, but I'm almost positive its because my injector seals are junk but I'm replacing them hopefully this saturday so ill let you know if there's a change
Posting Guru
Joined: Nov 2007
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From: West Texas
Was your AC running? If so that can do it. You really should hold the idle up to about 1000-1200 when idling with the ac on. It will keep the pressures from spiking on the high side and help the engine run easier.
Even on a big truck with a series 60 detroit, if the ac high side pressure gets too high you will feel it dragging on the engine at idle. Right before the relief valve blows.
If it was real cold out then it's possible that your ebpv valve was closing. That will cause the same feeling as you describe too.
Even on a big truck with a series 60 detroit, if the ac high side pressure gets too high you will feel it dragging on the engine at idle. Right before the relief valve blows.
If it was real cold out then it's possible that your ebpv valve was closing. That will cause the same feeling as you describe too.
