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2000 Ford Expedition throttle surges


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NaymzJaymz
User

Nov 11, 2012, 5:22 PM

Post #1 of 4 (5677 views)
2000 Ford Expedition throttle surges Sign In

Hello,
My vehicle is a 2000 Ford Expedition with a Triton V8 engine and mileage of 162,000. It has been very reliable and recently smogged easily, but the idle has become erratic with throttle surges at idle in park that are very noticable on the tach. Once warmed up it seems to drive fine out on the road at driving speeds, but the problem is evident immediately at any particular stop. I also notice that the engine seems to go to a higher rpm than before at intitial start up for about ten seconds before ildleing down. I just changed the fuel filter. Could it be the fuel pump, the TPS,? The check engine light is on. Any help would be appreciated. Thanks.


nickwarner
Veteran / Moderator
nickwarner profile image

Nov 11, 2012, 5:36 PM

Post #2 of 4 (5666 views)
Re: 2000 Ford Expedition throttle surges Sign In

An excellent idea to change your fuel filter, as it is regular maintenance. On my own cars I do it every year. Your check engine light is on, so you need to get the codes pulled and post them here. Most parts stores will do this for free. We need exact code numbers, not the generic description/probable causes crap that places like autozone give you. Under no circumstances should you buy parts based on the counter monkey's advice, just get the codes and tell us. They aren't mechanics, they are salesmen who happen to sell items of an automotive nature.

One thing worth doing especially at your mileage is to clean the back of your throttle plate. With the engine off, take off the air intake ducting and hold the throttle wide open. Spray carb cleaner and use an old toothbrush to scrub the plate free of soot. If you have someone who can help its a nice thing if they hold the throttle down for you, or just throw a brick on the pedal. Pay special attention to the idle air control passages, and if you can get the IAC motor out easily do so and clean both it and its bore until shiny. Should the idle surging persist, replace the IAC motor. But realize that even a new IAC cannot function properly in a gummed up bore and will exhibit the same symptoms either immediately or shortly after install. It must have a clean area to work in.

Please post back with codes and the results of your throttle plate cleaning so we can fine tune the diagnosis to the problem at hand.


NaymzJaymz
User

Nov 18, 2012, 12:57 PM

Post #3 of 4 (5600 views)
Re: 2000 Ford Expedition throttle surges Sign In

First of all Nick, thanks for your help. I'm glad I did something right by changing the fuel filter. The IAC stands for "idle air control", right? Since I'm very inexperienced, I will consult the shop manual to recognize the IAC motor specifically. I actually took it to a mechanic who found a huge vacuum leak and had it running extemely better within minutes. I believe you a right on about needing to clean the IAC bore. Is it likely to be the IAC motor itself? Do they go bad often?
I'm a little bit skittish about digging into this rig since it's our family car. This does sound like a pretty easy job that I'm not likely to mess up. As for the fault codes, I diconnected the battery and the check engine light went off. I also did this before smogging it when it smogged easily. I know this isn't the smartest thing to do, but could the vacuum leak that the mechanic fixed be the reason for the check engine light being on? I have one of those OBD units for finding fault codes. I've never used it, but perhaps I can get a fault code. That's very good advice for the auto parts store that you mentioned. I'm sorry to sound so naive and unsure of my abilities, but I suppose that's the point of forums like this. It"s awesome that experienced mechanics like you are helping those of us who need it. Thanks again.


Sidom
Veteran / Moderator
Sidom profile image

Nov 18, 2012, 1:16 PM

Post #4 of 4 (5597 views)
Re: 2000 Ford Expedition throttle surges Sign In

Follow all of Nicks advise....As he said you should be doing this as part of a normal maintenance schedule.

Also check the PCV hose & other vacuum lines to make sure there are no vaccum leaks, if there are then it probably set a P0171 & P0174, lean bank codes....






 
 
 






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