Originally Posted by oramman87
So just got the time to do a compression test all 4 were at 175. The plugs which are ndk double plats are fouled bad. I got a set of motor craft plugs for free and same thing fouled them out. Still a rough and choppy idle and then stalls.
oooook.... fouled how, and what was your gap and plugs exactly? We have had issues with parts stores giving the wrong plugs for these engines since there were 2 different 2.0 4 cyls available that year. If those plugs weren't for a Focus specifically, are you sure the heat range is correct?
You turn on the AC, and it stalls. That is typically the domain of the IAC to prevent that from happening. Regardless of the fact that you just changed the IAC- something is wrong. It might not be the part, it might be in the intake manifold- clogged up. Due to Murphy's Law- that's why you were able to change it in record time.
The only other thing you might need to check here is the TPS signal, and the throttle plate position. Hopefully nobody got in there and messed with the throttle plate stop screw that some non-car knowing peeps seem to think is an idle screw.
I would also double check the wiring to the IAC to see if it passes by things that might've burned into it. We've also had some running problems associated with the coil wiring where the harness is melted near the EGR tube -the metal one from the exhaust. Yanking on individual coil wires is a way to test if the pigtail is the issue. In your case, it does seem to point to the IAC being faulty- however, you likely have multiple issues. Get the IAC working first, then we'll move on.
Please... for goodness sake stop spraying stuff around to find vacuum leaks. That only works to double check large leaks like intake manifold leaks. Nobody is going to find a little 1/8" or 1/4" vacuum line leak that isn't making a hissing sound with carb cleaner or starting fluid. There are only like 6 vacuum lines on the VECI- is that too much to remove and visually inspect? It's not like you're diagnosing some 80's feedback carb with 40+ lines.
I hope that's of some help. And yes, please let us know what those plugs are exactly as in the part number, or verify that the plugs are for the Focus Zetec engine. Then move on to figure out (hopefully wiring) why the IAC isn't functioning properly.