So I have been trying to fix some of the issues with my Ford Escape. It started with engine light and a bad coil. The bad idle problem was there as well. I replaced all of the spark plugs, all of the coil packs, both sets of intake gaskets and that really helped the car with just general running right and fixed the engine light. I still had poor idle when in drive or reverse, just really rough, but otherwise seemed to be running fine.

I knew the car was about to hit 100k and I had been told by the Oil Change places, it needed a new Serpentine belt, so I replaced that. Still bad idle, I then cleaned the throttle body, the Idle Air Control valve and the mass air flow sensor, still bad idle. Then I replaced the fuel flow filter, still bad idle.

I've looking for vacuum leaks as best as I know how using the mass air flow cleaner and just trying to listen for one, but I can't find anything. That is not to say there isn't something there, I would probably need a mechanic to test it for sure.

With all of that said, would you guys say my best next step is replacing the Idle Air Control valve? I would have done it already if I thought it indicated that, but when I unplug it, it runs really bad and almost dies and when I plug it back in, it seems to do what it is supposed to do which is even the car out.

I plan on putting some seafoam in to see if that might help clean the injectors but my guess is that won't help either.

I welcome any input anyone has. Thanks all.

 

Check that you did not swap the front wiring loom for the COPs. I do not know vintage, but the loom changed such that it no longer laid across the 'upper' edge of the cam cover, and made a u-turn to connect to the COPs, but instead fed in from the 'left' and connected neatly to the COPs for cylinders 4-5-6.
If you have a 'dead miss' and can pull 4 or 6 COP wires without change, swap the loom end for end and see if that makes it all better.
If the miss is intermittent, it is not likely a swapped loom.
If the boots on the COPs have gotten oiled, by leaking cam cover O-rings around the plug well, they will likely allow for misfire. That problem will generally be an intermittent.
tom

 

Here's the thing, I don't think I am missing. I get no codes at all, I just have a rough idle. I really don't know what to do next besides take it somewhere they can run in depth diagnostics on it. I could replace the IAC but it likely is not that just because it seems like it is behaving like it should when I disconnect it.

 

The IAC is used to control the idle rpm. It compensates for loads, under command of the computer, such as the putting the gear selector into a driven range, A/C compressor and hydraulic power steering pump. It also provides a fast idle when the engine is cold, stepping the idle down as the engine warms up.
If it does all these w/o problem, it would be deemed functional to me. If the engine is not misfiring, and the idle is maintained, I don't know what the symptom is. Vibration?
tom