High Idle

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My idle has sped up to about 1000 RPM when engine is at operating temp, in drive, and AC on. This just occurred yesterday. Book says idle should be about 780 to 850 when in drive with AC on. Anyone have any tips on why idle has sped up? No error codes detected. Should I just adjust the low idle adjustment screw? Could my torque converter be on its way out? Any ideas?

Thanks in advance. Joe

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1995 2500 SLT 4x4 Club Cab, LWB, AT, 4. 1 LS, OEM Tow Hooks, Air Bags, 265/75/R16 BFG AT, Custom Rear Lights

 

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Joe,

The first thing I would check for is a frayed or sticking throttle cable. Disconnect the throttle cable from the linkage at the TPS and see if it still idles fast. If that doesn't do it, then check to see if the lock nut on the idle adjustment is loose or has fallen off. If that doesn't do it, disconnect the kick down cable to the transmission from the linkage at the TPS and see it that takes care of it. If that doesn't do it, then check to see if the two screws that attach the linkage lever to the pump lever are loose. If they are use an 8mm wrench to tighten them. If that doesn't do it, maybe the ball joints on the ends of the throttle rod from the linkage at the TPS to the pump need to be lubed. I put a little dab of grease in them as part of my normal service at oil change time. The ends of this rod are attached with funny little wire clips that have to be removed. If you can figure it out they can be removed with your fingers. Actually, that's the easiest way. Feel around the base of the ball part of the rod end. You will find a small wire fold that sticks out less than 1/8". Pull that loose in a counter clock wise motion in relation to the rod. Then pull it back along the rod and it will come out of the ball end. Don't drop the little thing. Once that clip is out you can pop the ball end off the lever with a screw driver. If that doesn't do it, I'm out of ideas.

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,BD valve body,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver

 

[Archive]

It sounds like your cable or linkage may be binding. Look closely to see if your linkage stop is even touching the idle adjustment screw when there is no pressure on the accelerator pedal. Your cable may also be frayed and binding in the cable housing if you don't have a newer style cable. If none of these problems are found, I would adjust the idle and see if it stays at the proper setting.

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Ron

'96 Club Cab 2500 4x4, 4:10LS, Auto, BD Pressure Loc, Mystery Switch,TST 230/605, Cummins Chrome, Mag-Hytec rear and trans covers, Boost, Pyro and trans gauges, Optima Red Tops, All black. Tow 14k HitchHiker triple glide 5th Whl. Also use 9. 5' Lance. NRA Life Member.

 

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Thanks guys for the brainstorming. I replaced my frayed skinny weak throttle and speed control cables last April so I know about those little bitty clips on the throttle rod. I gave it a once over and it didn't appear that anything was sticking. Joe, it sounds like a good idea to lube that rod up so that's what'll do.

 

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Is there anything wrong with it having a little higher idle? It's better then having a low idle which doesn't burn fuel completely right? After installing the BD Spring Kit my idle was raised and is a little under 1000 and in the 900 range compared to it being in the 700-600 range before.

Kyle

 

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With a high idle I have to drive with the brakes on as I idle through parking lots and such. Its anoying. Just this morning I backed into a rockery wall cause I wasn't used to the increased speed at idle. Lucky I have a big tow hitch to save my bumper (at the expense of someone else's #ad
. joe

 

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Joe, I had a similar problem with my 95. When it was 3 years old, the idle would run at 1000 to 1200rpm after at least 3 hours of non stop highway driving. After a short cool down it would idle a 750. I checked all the usual things and lubed everything in the area, to no avail. Last year the truck was getting hard to start in the morning so I had the dealer replace the rubber fuel return line. Presto, No more high idle on long trips. I don't have a clue if this could be related to anything, but it works for me! #ad


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1995 2500 SLT Club 4x4, auto, 3. 54, 3300 pound Elkhorn slide in camper, AirLift air springs, Ricka dual wheel adapters, K&N, DC tow hooks, Rancho RS9000, Hellwig rear sway bar.
101,000 miles and counting.

 

[Archive]

I had a high idle problem with my 98. (It scared the $h%t out of me more than a few times) I had it back to the dealer where I bought it, to no avail. I went to the local dealer (disgusted with spending a whole day off at the dealer where I bought it, just to have it NOT FIXED) and they said there was a TSB on this problem.
I don't know what it was exactly, the mechanic was already gone for the day, but I think it was the linkage on the side of the inj. pump. HTH

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98 Quad cab 4X4 2500 12 valve,5 speed,3. 54 rears, 8' bed. Boost and egt gauges but basicly stock.