Alright so I've been reading on the forum and it sounds like all these symptoms are common,but the solution is not.

Here is what I got:

2000 F-150 5.4L V8
-K&N air filter
-Dual exhaust (on before I purchased)

Problem:
My truck idles rough when sitting for awhile in a driveway(in park),while going through drive thrus(in drive),sitting at traffic lights/signs(in drive). The truck also will stall occasionally when coming to a stop.While driving the truck surges up and down while accelerating(very noticeable between 40-50mph.The check engine light was yellow and when I would give it gas it would occasionally start flashing. Once I replaced the 02 the light cleared. I relearned the system and have drove the truck about 25mi. No light but same problem.

Things done recently:
-changed fuel filter
-cleaned MAF sensor
-cleaned air filter
-replaced front passenger O2 sensor.

Any suggestions that you have from experience with this issue would be greatly appreciated.

 

2 things. Surging at 40-50mph is usually caused by a misfire due to bad COPS. I actually have a set of OEM's for sale in the For Sale section of this forum. (https://www.f150forum.com/f63/8-oem-...-coils-244061/)


Also, the IAC valve is known to cause rough, fluctuating idle and stalling.

 

Anyway to tell which COP is bad without replacing them all. Or better yet can you get to them all to replace or is it a pain like the plugs?

 

You'll either need it to misfire enough to throw a code or you will need a scanner capable of reading live data in mode 6.

They are easier than plugs since you don't need all sorts of extensions, joints or torque wrench. Its an hour or two task. They are not difficult to get to with a 7mm swivel.

 

Thanks Tackle. I'm gonna give it a try on my next day off.

 

So it's been awhile, but I tried a few things to see if it would help.First I noticed two hoses part of the dpfe were torn so I replaced them. Then I pulled both the TB and the IAC and cleaned the crud out of them. After reinstalling I thought maybe I needed to unplug the battery and go through the steps of resetting the fuel/air trim. As I drove the truck around for 20mi or so it is doing the same thing. Upon acceleration it chugs and when I let of the gas the rpms drop way doen. So bad that if I sit at a stop for more than 10sec it starts fluttering up and down between 400-600 rpms. Any ideas? Starting to get really frustrated and about to throw in the towel on this thing.

 

If check engine light is not on it must be IAC valve, otherwise it sound like misfire, suggest cleaning it or perhaps replacing, on 5.4 its located behind the TB

 

So here is an update. I finally got my cell to come on again and I'm having a lean bank 1 sensor 2 code. I went ahead and replaced the code figuring since they were original it couldn't hurt. The actual driving of the truck seems to have gotten better. However when I come to a stop and wait about 10sec the rpms start fluctuating between 500-700 still. Also when I let off the gas the Rpms drop instantly instead of slowly falling. When in park the truck idles fine for awhile then idles rough then smooths out again. Any ideas guys?

 

Anybody got any guess what might be going on? My light is back on so I'm gonna have someone scan it again. I'm thinking possibly a bad injector or cop. Any ways to find the bad one instead of replacing them all. I'm willing to spend the money to fix it right but I want to make sure it will definitely be right.

 

You can check the COP's while engine is running by unplugging one at a time. If it misfires when you unplug it then it is good. The one that makes no change is going to be the bad one. Very possible the plug may be fowled as well