Idling probelms in a 98
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Idling probelms in a 98
My truck has started givin me grief again. When I push in the clutch the rpm will hang around 1800 or even rise up to 2000 for 30 seconds or so, then drop down to 600. It will do this whether the engine is cold or warm, if the transmission is in gear with the clutch in or shifted into nuetral, doesnt matter. The clutch and hydraulic system are in good working order, no significant wear on the clutch, system is new and full of fluid with no air bubbles. No check engine light is on. Am I looking at a sensor, vaccuum leak, IAC??? These new vehicles are just too complicated and finicky for my tastes. I'm going back to something older and simpler when I'm done with grad school.
Laughing Gas
Joined: Jun 2005
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I have the same problem with my 98. I’ve been working on it for about a year and haven’t found the bug yet. My best guess right now is I have a vacuum leak but lord only knows where it’s at. I’ve gotten frustrated with it and, as much as I hate to admit it, I’ve gotten to the point where I’ve stopped troubleshooting and I’m just swapping parts. So I’m probably not much help but if you find the problem make sure you post it. Hopefully that it will point me in the right direction.
Logistics Pro
Joined: Jan 2002
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From: suburban atlanta
Is this a new 'feature'? Did it turn itself on instantaneously or was it gradual? Has any work been done that could possibly affect the idle?
What year/model? Try disconnecting the IAC to see if the problem goes away. I had a shorted regulator that caused the engine to die when I shifted from D to N or Park. So much hash in the DC that it must have confused the IAC. Replaced the regulator, no more stall when shifting to neutral. You might have something similar blowing the IAC out of the water. Remember, the clutch is connected to the ECM, as you must depress the clutch for the starter to work, so there is a feedback loop possible...
tom
What year/model? Try disconnecting the IAC to see if the problem goes away. I had a shorted regulator that caused the engine to die when I shifted from D to N or Park. So much hash in the DC that it must have confused the IAC. Replaced the regulator, no more stall when shifting to neutral. You might have something similar blowing the IAC out of the water. Remember, the clutch is connected to the ECM, as you must depress the clutch for the starter to work, so there is a feedback loop possible...
tom
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My truck has started givin me grief again. When I push in the clutch the rpm will hang around 1800 or even rise up to 2000 for 30 seconds or so, then drop down to 600. It will do this whether the engine is cold or warm, if the transmission is in gear with the clutch in or shifted into nuetral, doesnt matter. The clutch and hydraulic system are in good working order, no significant wear on the clutch, system is new and full of fluid with no air bubbles. No check engine light is on. Am I looking at a sensor, vaccuum leak, IAC???
These new vehicles are just too complicated and finicky for my tastes. I'm going back to something older and simpler when I'm done with grad school.
These new vehicles are just too complicated and finicky for my tastes. I'm going back to something older and simpler when I'm done with grad school.
As Tom suggested, begin with the IAC, maybe pull & clean it with a good quality throttle body spray cleaner & see if you get good results. Ford doesn't recommend cleaning the IAC, as results sometimes don't last, but it's inexpensive, easy to go & if you get positive results that don't last, at least you'll know whats wrong & that IAC replacement will likely bring joy!!!!
If that doesn't get results, maybe pull & clean the throttle body, with the remainder of the TB spray, paying close attention to deposits on the edges of the throttle plate & being careful not to damage/remove the TB non stick coating.
If still no joy, have a close look for binding of the accelerator cable or linkage, all the way to the TB.
Just a bunch more thoughts for consideration, let us know how it goes.
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Ok I got a pcv a few months ago but for some stupid reason I can't find the darn thing even with instructions, anybody have a picture of where its at. Hopefully I can get some free time this weekend to clean the IAC but between classes and research these next few months are gonna be heck! Is there a vaccuum diagram for the truck anywhere? I had one for my old ram which made things a lot easier. Thanks for the help guys, I'll give the IAC and PCV a shot and get back to you.
Logistics Pro
Joined: Jan 2002
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From: suburban atlanta
Is this a 4 or 6? What year? The PCV for the 4's (pre dohc models) is located 'in-line' under the intake manifold. You will get a new one with an elbow in the package, which you discard. The hose from the side of the block up to the bottom of the intake near the throttle plate has the PCV valve embedded.
tom
tom
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From: Connecticut
Postmaster
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From: St. Peter
To check for vac leaks, get a propane torch (dont light it, just turn the propane on). and move it over the seams of the intake manifold, and anything else that holds vacuum while the engine is running. If the engine starts to sputter, you know that it is getting the propane. Keep doing this until you the engine drops RPM. You can also use brake cleaner, but it is a bit harsh on rubber parts, and in the case of a fire, it is liquid and will burn on whatever you have it on, while propane will just burn your eyelashes off.
I would be suspect of your IAC valve.
I would be suspect of your IAC valve.
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I was thumbin around Napaonline to get a picture of the IAC valve so I know what I'm lookin for, it looks like theres going to be a gasket on this thing. Is that so? Do I need to replace it or can I blue glue it?
Post Fiend
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From: Connecticut
If your 2.3L IAC is like my 4.0L, there is a small rubber o-ring type gasket that fits in a groove around the flange which in most cases can be re-used.
Most aftermarket IACs come with their own gasket in the box, although it's usually a different style gasket than the original. If the original gasket is worn down thin or torn then you should use the one in the box. You won't need any goop-type sealer for the new gasket (maybe a shot of some Permatex Copper Spray-A-Gasket, at most).
Most aftermarket IACs come with their own gasket in the box, although it's usually a different style gasket than the original. If the original gasket is worn down thin or torn then you should use the one in the box. You won't need any goop-type sealer for the new gasket (maybe a shot of some Permatex Copper Spray-A-Gasket, at most).