Rough Idle, Help!
 

Hey, guys. I have a 1985 F150 with a 300 Inline 4.9l. I have changed plugs, plug wires, air filter, battery ground cable, fuel filter, and fixed a couple of vacuum leaks I found. When I got this truck, somebody had removed the A/C system and a lot of the wiring under the hood has been discontinued or spliced into. That's what I'm most afraid of. I have sprayed my vacuum connections to check for additional leaks, but nothing is jumping out at me. There are a lot of vacuum ports that have been capped, as well. The truck cranks right up and runs, just not smooth. I have tried to adjust timing a little at the rotor. This truck has the electronic timing, so there's not much you can do but change the ignition module. My understanding on those is that they either work, or they don't. Changing the module or the ignition coil are next in line, I guess. What am I missing?

I believe that it is a carberated engine ? If so check to see if the carb is loose by wiggling it. Common problem with them. How did it run before you did the tune up ? Timing is adjustable without replacing the module...What plugs did you put in ?

It is carbureted, but the carb isn't loose. It was running rough already, and that's why I started working through some of the easy stuff. The plugs I put in it are NOS Champions that I happened to have from a bulk parts purchase that showed to be compatible. I gapped them according to the chart in my Chilton Manual.

Well, i`m afraid you have many possibility`s,,,wrong PCV ,,plugged up carb running lean,,sticky valves,,vac leak,,sticky EGR valve,,low compression,,just to name a few..Fords generally don`t like champions or jobber PCV`s. ( don`t worry about the plugs yet ) but check PCV and replace with a ford one if needed, ..When you check to see if carb is loose, you have to twist it not shake it ,,Best i can come up without actually seeing it

Yeah, I knew the options were limitless at this point, but you have given me some other leads to chase. Thanks for the replies. I will update once I have had a chance to look at some of these things.

Here is my current setup for pcv. Definitely don't think the valve cover attachment is factory, much less the hose setup. This is somewhat loose in the cover and is inserted to the point that it makes contact with a flat surface underneath.

Yep you got some cleaning up to do.. The joys of previous butchery . lol

FORD TUFF, what I have attached to the valve cover is simply a wide open line and connector that runs up to the air filter box and quarter turn connects to the side. Is that all it is supposed to be? What about this setup constitutes a "valve"? I have seen some setups while searching (not sure if it is appropriate for my vehicle) that actually have a setup at the valve cover that include a vacuum line. Thanks for the help.

the pcv valve is computer controlled and doesnt just shunt right into the air filter, that would just be a vent. if you look way at the back there (just visible in the picture) there is another part that sticks into the valve cover, thats the pcv. it should have 2 vac lines into it, top one goes to one of the electrical switches that are attached to the side of the valve cover, the other should go into the intake under the carb somewhere. the vacuum should also continue from that electrical switch back into the manifold. there should be a diagram near the hood latch that details all this. the pcv valve is cheap enough i would just replace it, but you can soak it with carb cleaner until you hear it jiggle inside when you jiggle it outside =)

you replaced a lot of inginition components, but didnt list the cap and rotor, have you looked at those to see their condition?