funny idling and acceleration

dorn4ever · 07-10-2009, 02:04 AM

I have a 99 James with the 4.3 that has erratic idling and will accelerate or maintain speed without cruise on at around 30 to 40 mph. Also, sometimes if Im sitting at a red light it will want to go as if im on the gas a little. The engine light was on and the code said there was a problem with the idle air control. I replaced the IAC and it still does it so I thought it might be a vacuum problem. I was looking in the manual at the PCV (section 1-24) and it told me to take it out of the valve cover while running and feel for suction. There was no suction at all. It then said to shake it to hear a rattle and there is nothing there that would even move to make a rattle sound. sorry for the long post, just trying to explain the problem. Thanks for any help.

~~4x4zr2GA~~ · 07-10-2009, 02:15 AM

follow the vacuum line that the pcv attaches to... make sure it is hooked up at the other end. sounds to me like you might have a vacuum leak somehwere, which is sucking in un-metered air, so the computer is not accounting for it making the truck try to idle up. do you hear any loud "whiiiiiiirrrrrr" or air sucking sound?

dorn4ever · 07-11-2009, 05:32 PM

I know what you mean by a "sucking" sound, but i dont hear anything that would pinpoint a leak. i guess that doesnt necessarily mean there isnt a leak so I will keep looking. thanks, anything else?

dorn4ever · 07-11-2009, 10:20 PM

OK, so I found the pcv, the picture in the repair manual had me looking in the wrong spot. It has suction and does rattle when I shake it. Still didnt find a vacuum leak anywhere. Damn, whats the problem

akirsch2005 · 07-20-2009, 10:17 AM

well i dont know if they are the same but i had the same problem with mine its a 95 but its not the mass air motor like your its the spider injection one but anyways my sensor in the intake i think its the mass airflow sensor was not pluged in tight which caused it to do the high idealing

07-10-2009, 02:04 AM	#1
dorn4ever Registered User Age: 27 Join Date: May 2009 Posts: 8 Location: User is: OffLine	funny idling and acceleration I have a 99 James with the 4.3 that has erratic idling and will accelerate or maintain speed without cruise on at around 30 to 40 mph. Also, sometimes if Im sitting at a red light it will want to go as if im on the gas a little. The engine light was on and the code said there was a problem with the idle air control. I replaced the IAC and it still does it so I thought it might be a vacuum problem. I was looking in the manual at the PCV (section 1-24) and it told me to take it out of the valve cover while running and feel for suction. There was no suction at all. It then said to shake it to hear a rattle and there is nothing there that would even move to make a rattle sound. sorry for the long post, just trying to explain the problem. Thanks for any help.
	[Reply w/Quote]

07-10-2009, 02:15 AM	#2
~~4x4zr2GA~~ Banned Age: 23 Join Date: Feb 2006 Posts: 2,361 Location: warner robins, GA User is: OffLine	Re: funny idling and acceleration follow the vacuum line that the pcv attaches to... make sure it is hooked up at the other end. sounds to me like you might have a vacuum leak somehwere, which is sucking in un-metered air, so the computer is not accounting for it making the truck try to idle up. do you hear any loud "whiiiiiiirrrrrr" or air sucking sound?
	[Reply w/Quote]

07-11-2009, 05:32 PM	#3
dorn4ever Registered User Age: 27 Join Date: May 2009 Posts: 8 Location: User is: OffLine	Re: funny idling and acceleration I know what you mean by a "sucking" sound, but i dont hear anything that would pinpoint a leak. i guess that doesnt necessarily mean there isnt a leak so I will keep looking. thanks, anything else?
	[Reply w/Quote]

07-11-2009, 10:20 PM	#4
dorn4ever Registered User Age: 27 Join Date: May 2009 Posts: 8 Location: User is: OffLine	Re: funny idling and acceleration OK, so I found the pcv, the picture in the repair manual had me looking in the wrong spot. It has suction and does rattle when I shake it. Still didnt find a vacuum leak anywhere. Damn, whats the problem
	[Reply w/Quote]

07-20-2009, 10:17 AM	#5
akirsch2005 Registered User Age: 22 Join Date: Jul 2009 Posts: 3 Location: User is: OffLine	Re: funny idling and acceleration well i dont know if they are the same but i had the same problem with mine its a 95 but its not the mass air motor like your its the spider injection one but anyways my sensor in the intake i think its the mass airflow sensor was not pluged in tight which caused it to do the high idealing
	[Reply w/Quote]