Low Idle Issues
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Joined: Jun 2003
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From: SW VA
Low Idle Issues
I asked this question before...My truck ('97, 4.6L, auto) will bog down to around 450-500 RPM's when coming to a stop, and it will sputter and hesitate when I give it throttle to take off. It doesnt do this every time, but about 80% of the time once the truck is warmed up.
Also, It only does it when in a drive gear. While sitting at a stop light, I can shift into neutral and the RPM's will jump up to 750-800 where they should be. But once I shift back into drive, the RPM's fall back to around 500-600. I can hold the brake and rev the truck towards 1500RPM and let off the throttle slowly, and the RPM's will usually hold 750-800 by the time my foot is off the throttle (also while sitting at a light).
Sometimes, while driving down the road, if I let off the throttle I notice the RPM's drop well below normal, and the truck slows down faster than it should (engine braking).
I just replaced the IAC valve, and it didn't help at all. When I get a chance, I want to clean the MAF....I have no idea if the previous owner ever cleaned/replaced it or not. I've had the truck for 20K miles now (2 years).
Any ideas of what to check for possible solutions?
Also, It only does it when in a drive gear. While sitting at a stop light, I can shift into neutral and the RPM's will jump up to 750-800 where they should be. But once I shift back into drive, the RPM's fall back to around 500-600. I can hold the brake and rev the truck towards 1500RPM and let off the throttle slowly, and the RPM's will usually hold 750-800 by the time my foot is off the throttle (also while sitting at a light).
Sometimes, while driving down the road, if I let off the throttle I notice the RPM's drop well below normal, and the truck slows down faster than it should (engine braking).
I just replaced the IAC valve, and it didn't help at all. When I get a chance, I want to clean the MAF....I have no idea if the previous owner ever cleaned/replaced it or not. I've had the truck for 20K miles now (2 years).
Any ideas of what to check for possible solutions?
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Joined: Jun 2003
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From: SW VA
I ran seafoam through it not too long ago, but I need to do it again.
I will check the PCV valve when I get a chance. I doubt it has ever been changed (there's 100K on my truck). I just dont want to go replacing what I don't need to...I'm very tight on money. The IAC was $60...
*EDIT*
I forgot to ask...is there a way to check or clean the PCV vavle? I dont want to replace it just yet if I dont have to...
I will check the PCV valve when I get a chance. I doubt it has ever been changed (there's 100K on my truck). I just dont want to go replacing what I don't need to...I'm very tight on money. The IAC was $60...
*EDIT*
I forgot to ask...is there a way to check or clean the PCV vavle? I dont want to replace it just yet if I dont have to...
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Joined: Dec 2006
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Where have you guys been getting your auto parts? I got my IAC valve from Auto Zone and it cost me $42 and my PCV valve was $1.99 at Auto Zone also.I'm not trying to plug them but they were cheaper then anybody including rockauto.com. I dont think you can clean one because once the spring in it is worn out its had it.
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From: Napoleon Ohio
hey i have 01 5.4L f 150 and i changed everything that they told you to, and i found out that my problem was my tranny... my ford dealer said it was a shutter that gets stuck open or closed when you shift (mine was in second gear mosly) but when it happened it idled about 4-500rpm and vibrated when i accelerated so you might want to look into that too
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Joined: Jun 2003
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From: SW VA
Alright...I bought the PCV valve, but havent had time to replace it yet. $3 at AdvanceAuto...I was thinking it was going to be $30-$40...
FYI, I paid $60 at a dealership for the IAC.
BlueWolf: Yes, the spark plugs and wires are all origional. Other than the IAC and the Alternator...everything on the truck is origional (even the rotors).
Thanks for all the information. I should have time tomorrow morning to change it.
FYI, I paid $60 at a dealership for the IAC.
BlueWolf: Yes, the spark plugs and wires are all origional. Other than the IAC and the Alternator...everything on the truck is origional (even the rotors).
Thanks for all the information. I should have time tomorrow morning to change it.
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