- #46 of 65
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Re: 98 jimmy dies [98jimmy]
by repairdog
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Jul 18, 2007 (2:11 pm)
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Replying to: 98jimmy (Jul 18, 2007 8:00 am)
Idle air control (IAC) valve on the throttle body - replace it and that is controlled by the PCM and sets the idle and mixture. Have to pull the throttle body off to remove the side mounting screws and clean inside the air passage seat area so the new plunger fits cleanly. Part about $75 (aftermarket)-125(GM). If only at or approaching an idle that the intermittent part. They must of tested the fuel pressure already.
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- #47 of 65
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Re: 98 jimmy dies [repairdog]
by 98jimmy
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Jul 19, 2007 (8:02 am)
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Replying to: repairdog (Jul 18, 2007 2:11 pm)
Thanks for the input. This IAC will effect the engine dying at 80 mph as well as at idle? This problem does occur at any speed as long as the weather is warm enough.
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- #48 of 65
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Re: 98 jimmy dies [98jimmy]
by repairdog
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Jul 21, 2007 (4:03 am)
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Replying to: 98jimmy (Jul 19, 2007 8:02 am)
No, at idle or as rpms drop to 600 so at 80 that wouldn't happen. I would put a new cap/rotor on and not a cheapo but use a Delco or Standard Motors Product one. Rules that out. Then on to wires, plugs, intermittent sensors (such as crank position sensor under front that tells PCM where to fire plugs), clean the MAF sensor, is the temp gauge reading correctly as it also feeds the PCM, then again check that fuel pressure hot at test port. These ones are a pain to find. Then theres always the coil and ign module, the cam position sensor in the dist, and loose grounds or othetr wires or connector plug ins - sorry.
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- #49 of 65
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Re: 98 jimmy dies [repairdog]
by 98jimmy
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Jul 21, 2007 (5:30 am)
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Replying to: repairdog (Jul 21, 2007 4:03 am)
Thanks for the list. I will start at the top and see if anything helps. Again thanks for taking the time
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- #50 of 65
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Engine revving - sporadic
by rickwb
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Aug 10, 2007 (9:13 pm)
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- #51 of 65
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Engine revving - sporatic
by rickwb
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Jul 30, 2007 (5:08 pm)
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NEW BOARD MEMBER HERE - My daughter's 2001 4.3 liter gmc jimmy sometimes revs to about 3000 rpms when the clutch is depressed. IF however you let the engine rpms drop below 1100 rpms before depressing the clutch the engine will idle normally. Also if the engine is shut off and restarted the engine will idle and return to idle normally if the accelerater is depressed and released, After some period at speed however the engine will rev to about 300 rpms again when the clutch is depressed. Seems to occur mostly when engine is warm and did go quite some time between the last couple of occurances. Sometimes will act up on a regular basis then go away for a while. I'd appreciate any guideance I can get. Thanks in advance.
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- #52 of 65
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Re: Engine revving - sporatic [rickwb]
by tidester HOST
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Jul 30, 2007 (8:34 pm)
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Replying to: rickwb (Jul 30, 2007 5:08 pm)
Please don't take this the wrong way but have you experienced the high revving yourself? Because you said it was your daughter's Jimmy I'm just wondering whether it's inexperience at driving a manual. It takes a little time for beginners to properly synchronize easing off on the gas while pressing the clutch pedal.
tidester, host
SUVs and Smart Shopper
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- #53 of 65
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Re: Engine revving - sporatic [tidester]
by rickwb
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Jul 30, 2007 (9:05 pm)
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Replying to: tidester (Jul 30, 2007 8:34 pm)
Thanks for the reply - Yes I have experienced this myself on several instances. The latest was just an hour or so before my original post. It is very strange. Mostly occurs after some amount of highway driving and acts just like I described. Push in the clutch and the engine rpms go to about 3000. BUT if I get the rpms low (below 1100 in gear) before depressing the clutch the rpms will stay at idle until accelerating and shifting up through the gears. At that time the engine rpms will rise to 3000 rpms again ( and stay there) when the clutch is depressed. This occurs when shifting anywhere above the 1100 or so rpms I described earlier. I have removed my foot completly from the accelerator pedal and it still occurs. I hooked my toe under the accelerator and lifted thinking it was possibly sticking with no luck. Operator inexperience is not an issue here. This started after owning this vehicle for a couple of years and this is her 3rd vehicle with standard transmission. Thanks again. Hopefully some fresh minds will get me pointed in the right direction.
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- #54 of 65
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Re: Engine revving - sporatic [rickwb]
by grose67
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Jul 31, 2007 (8:56 am)
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Replying to: rickwb (Jul 30, 2007 9:05 pm)
I had the same type of sporadic issue a couple of years ago on my 95 Blazer. The idle speed controller was going out.
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- #55 of 65
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Re: Engine revving - sporatic [grose67]
by rickwb
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Aug 02, 2007 (5:25 am)
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Replying to: grose67 (Jul 31, 2007 8:56 am)
Grose67 - Thanks for the input. This has been a stumper. Maybe we can get headed the the right direction now....
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