I have an 89 F150 with 80K miles with and auto 4.9 L Six that lopes when at idle and I can't seem to figure out what is causing it. I am getting some black smoke out of the exhaust and it also seems to be running rich. The truck has been infrequently used for years, so I believe some of my issues derived from sitting. It originally idled a bit high, so an attempt to check the timing has turned into a huge mistake, as I have not been able to set the timing correctly with the loping. I had a mechanic attempt to clean the injectors with seafoam which led me to replace all of the injectors with new. Once I replaced the injectors, I installed new Motorcraft plugs (plugs were fouled), fired it up and it still has a rough idle. Basically it will go from normal RPM to low RPM's and back and it sometimes cuts off. So far, I have not gotten any codes, however I will go check them again and add the results to this post. The soot coming out of the tail pipe concerns me. Maybe I need to pull the head.....Any suggestion/assistance would be appreciated. Below are items that I have done to no avail.

 

I ran a KOEO test with my innova code reader and got a code 33 and an 11. The 33 is supposed to be an EGR fail to close code and the 11 is system normal. Go figure Excess fuel seems to be the main issue that I am having. I would assume that replacing the EGR valve would not make much difference when it comes to fouling the plugs. I will keep posting to follow my progress.

 

There are a number of things that can cause a rich condition:

The main causes are:

Bad MAP sensor ( or broken vacuum line going to MAP sensor)
Bad O2 sensor
Bad coolant temperature sensor.

Also, you can't get a 11 and a 33 code together. If you did, I would suspect a bad connection to the computer, or a failing computer.

 

Thanks Lead Head. I wen't ahead and bought a fuel pressure regulator just for kicks. I then inspected my vacuum tubing and found fuel in the line to the MAP sensor which seemed odd. I then replaced the FPR, set the timing back like it was supposed to be and now she runs like a champ.