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I have a 97 F150 ext cab 4x4 4.6 L with 147,000 miles. The last week the weather here in Michigan has been into the 90's every day. My truck seems to run fine in the morning, but in the afternoon, I start it up and seems to be fine until I stop and then has no power(no fuel?). Low RPM's and sometimes it will stall. Usually if I pull over and turn off the key it will start right up and go perfect again until I slow down and or stop. I have changed the fuel filter, run fuel injector cleaner also. PLEASE HELP!!! thx!!!
I had a similar problem with a cheby car I once had and it wound up being a bad fuel cap. The bad cap wasn't allowing it to vent, and it was getting vapor locked. Could be the same thing maybe???
had the same issue not too long ago... torque converter was locked up in low gear and would stall the motor gradually at a stop... i gave her a the beans a bit and i have not had the issue since... happened in the hot weather.... but now after all of the rain i have another issue
Possibly a bad or carboned-up Idle Air Control valve, more commonly known around here as the IAC valve. Quite a few posts on this topic on this board. You might want to do a site search.
had the same issue not too long ago... torque converter was locked up in low gear and would stall the motor gradually at a stop... i gave her a the beans a bit and i have not had the issue since... happened in the hot weather.... but now after all of the rain i have another issue
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kdbbmanton - Check your IAC as mentioned before. (Idle Air Control valve). With the heat, fuel will burn differently and can cause more carbon buildup inside of it. Or it could of just been timing and is dirty. It is located at the top back of your intake manifold. Remove the plastic manifold cover, (3 bolts), and you will see the IAC. Remove the two bolts and unplug the wiring harness. I used brake cleaner to clean mine. Just sprayed it in the and let it drain out. Dont let it sit in there though. Just spray and drain. You will see all the black ca-ca flowing out. Let it dry up really good or blow it out with an airhose, then put it back in. If it runs better, then look at getting another one. They cost about $70 depending on where you are at. It is a pretty common item for issues at idle.
If all that does not work check your fuel presser at the valve on the fuel rail, it it is lower then the proper specs then the fuel pump could be going out. I am not shure what the pressure should be but probably between 30 and 45 punds per square inch. check first for the proper specs.
BillyBob made a good point that cleaning the IAC will only buy you a little time. You probably have to wind up buying a new one. One other point is that the IAC and the engine management software essentially communicate with one another. A cleaned IAC will behave a little more efficiently than it did while it was dirty. Before you remove it to clean it, remove the negative battery cable for a little awhile. The idea is to deprive the engine computer of current long enough to force it into a learning mode which will force the computer to become reacquainted with the newly cleaned IAC. You'll know that you left the cable off long enough if, just after you start the engine for the first time after reconnecting the cable, all the instrument panel guage needles do a sweep across the guage faces.
I'm changing my IAC for the same reason you have. My truck will stall & not take gas unless pop the hood & tap the valve. I cleaned it & got about 200 miles & its stalling again. Its the third one in 117000 miles. Common problem on the mod motors
I used to have the 4.0 ranger, when the IAC valve went bad the truck would howl like a dog. Well now on my 5.4 with 42,000 miles the thing at idle, just like the ranger is howling like a dog. My problem is I want to try and clean the IAC first before I buy one, but where is it? Does anyone have any pics? I tried taking off a sensor on the throttle body but when I took it off it was more like a throttle position sensor. Next to that was another looking sensor with a plug connector and a couple of vacuum hoses is that it? Please Help cause my local rip off dealer is trying to tell me labor, parts, etc. well you guys all know what the dealer wants $$$$$$$$$.
Thanks Billybob69 I will take another look tonight when I get home and double check to see if I can get to it or even clean it to see if the noise goes away.
The IAC will be held on with 2 bolts, and have a 2 or 3 wire harness. When you look into it after removing it, you will see what looks like 2 round sections side by side, leading into the valve section off of 1 of the "barrels".
Billybob69 thanks I found the valve last night. I put a fan on the engine to cool it down faster when I got home last night. I sprayed some PB blaster on the to bolts and used a small ratchet to remove the bolts, tight fit but not to bad. I then cleaned out the IAC valve with Throttle Body Cleaner and the howling noise went away for about 20 minutes then came back. I am now pretty sure this is what I need to replace. The dealer had it in stock for $89.25 and a Discount parts store said 3-5 days and $49 but I don't think the parts store has the right part cause they called it an IAC motor not valve. I know the one guy at the dealer so i should be able to get a better price then $89.25. I will let all of you know if this solves my noise problem.
P.S. I also had disconnected the negitive side of the battery before even working on the truck to reset the computer.