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Hello all,
I bought a 1996 Ford F150 Eddie Baurer edition. As I was driving home I stopped to get gas and when I went to start it again it had an extremely rough idle. I got it home and it was idling fine until I shut it off and cranked it back over, it did the same. I drove it around my neighborhood and noticed that it was starting to surge when I go to take off. As I was driving back it began to misfire. Wanting to know if anybody has experienced this before. Going to pull the Check Engine codes tomorrow, I will report back with information.
Thank you for you help,
Matthew
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how was the performance upon acceleration? does this happen with both fuel tanks or on one of them? If it’s only one tank I would say fuel pump is bad, if it’s with both tanks, I’d say fuel filter is clogged up
it only has one fuel tank and the pump has been replaced when I shut the truck off i can hear a him coming from the drivers side like something isn’t sealing right. The check engine codes were for a number 4 misfire and running lean on both “banks”
the lean mixture would cause the misfire and sorry I assumed you had the twin tanks, most of your model trucks have the twins, anyways, the hum is a good thing because that mean the the fuel pump is working, the easiest thing to do for you is a simple fuel filter replacement, you don’t know how often this other guy who owned the truck before you did it if ever. A fuel filter for that truck is $25 but a real pain to do because of the “quick release” clips that require some special tool to get it out.
I’ll check that out tomorrow I was going to change it anyway and take it to my firends shop and get him to do a tune up (plugs, wires, cap, etc.) I think I’ve got the tool laying around somewhere from when I had to change out the fuel filter on my dads explorer.
Status report. I got it tuned up today and it seems to be running better but it still has a rough idle. I replaced the fuel filter, and had the plugs, wires, cap, and rotator replaced. My friends seem to think its is the IAC. Any further thoughts or recommendations.
It could be IAC, but rough idle and surging are usually caused by a vacuum leak. The easiest thing to test for is the vacuum leak. Check to make sure there aren’t any disconnected or broken vacuum hoses, and check them for cracks/splits. Don’t forget about the ‘big’ vacuum hoses like the brake booster and PCV. You can use a can of carb cleaner to spray around the hoses and engine while it is running, and if some gets sucked into the engine through a leak it will change the RPM of the engine. Propane from a propane torch (not lit of course) and a squirt bottle of water can also be used in the same way to find vacuum leaks. IAC issues are usually just dirt related, failures are quite rare. The IAC can be removed, cleaned, and re-installed (also clean the mating seat in the throttle body while the IAC is out).
I cleaned out the IAC and the throttle body. It doesn’t seem like it is surging anymore but is still idling rough. If you turn all of the electronics on it starts to almost stall out. Also happens only when its hot. Going to check for vacuum leaks
I believe that the egr is stuck closed because the pipe coming out of the exhaust manifold gets warm but not hot. Would this be a possible expination? If the truck runs until it gets up to 200° F it won’t start at all and when it does it sounds like it running like it barely makes it to the next revolution.
The EGR has nothing to do with the idle unless it’s stuck open. It’s an easy check. Just pull up on the diaphragm on the valve when the engine is running. If it runs rough or stalls, the EGR is working like it should. I would look for vacuum leaks as suggested. If you don’t find any, you might be onto something with the IAC being faulty. More info here.
http://www.ericthecarguy.com/faq/solving-automotive-idle-problems
Good luck and keep us posted.
Can you plug a scanner into it that can read live data? I’m curious what your fuel trims are at idling and at higher revs.
To add to what Eric said, the EGR is supposed to be closed at idle. It should only open at light throttle cruising. If the DPFE sensor was faulty it could allow the EGR to try to open. Pull the vacuum line off the EGR valve and feel it to see if there is vacuum present. There should not be at idle. To see if the EGR valve is stuck you can use the test Eric mentioned, which is both fast and effective.
Does it make a difference in the idle if you have your foot on the brake?
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