I have a 2001 Ford Focus ZX3 with 5 speed manual transmission, It’s got this crazy, occasional problem of idling too low (at about 300 rpms) when the car is started after driving it on a very hot day, it immediately will stall or takes some creative shifting and driving to keep it running. When it happens, it seems to take about 1/2 hr for everything to cool down enough before it will start normally again (and idle at about 700-1000 rpms) It only happens occasionally, at one point I thought it happened when I started the car with the A/C button still on, but I’ve proven that to be incorrect. I’ve had the fuel injection cleaned, replaced all the plugs and wires, thought that helped a little, but it’s happened again and I’ve had this car to three different shops (including the dealer) and they can’t see to replicate the problem. I’ve been told it could be an idle air controller, but nothing conclusive. Got any ideas on what’s causing the problem?
I would suspect that it is indeed the IAC. It’s not an expensive part to replace. You can tap on it (the IAC) with a small hammer when the engine is idling too low. It should speed up then if the IAC is sticking, a common issue for Fords of the late 90’s, early 2000’s.
I’m surprised that the repair shops have hesitating in changing it out, I think the dealership mentioned the same thing about tapping on it, but apparently wherever it’s mounted on this engine, I think they told me that it’s not that easy to do. Maybe I’ll just give it a whirl and get it replaced and see if it helps, it’s good to hear that it’s a common problem on older fords. Thanks very much for the advise!!
I have the SAME problem with my 2003 Ford Focus ZX3 with manual transmission. I can usually get it to go by gassing it and keeping the rmps high. Ive taken it to about 5 mechanics and none of them have figured it out. I have basically stopped driving the car but I think Im going to go ahead and try to replace the IAC valve as well. Or Im going to trade it in for a different car. I only have 67000 miles on it. 
You can start by just pulling the IAC and cleaning it with some throttle body cleaner. Also check and clean up its electrical connector.
Yeah, at least I’ve gotten 114K out of mine…it’s acually been a pretty reliable car overall, except for some suspension/front end problems. seems like a waste to junk the car because of this problem
great…is the idle air controller easy to find?
Did either of you figure out the low idle / stalling problem? I have the same issue with a 2003 Ford Focus ZX3. Been to 4 mechanics and no luck.
Sorry for delay…I did have my idle air controller replaced by ford dealer and so far I haven’t had any problems (knock on wood). Don’t replaced the mass airflow sensor, the first shop worked with talked me into replacing that, but it didn’t fix problem.
So far, so good, and it’s been plenty hot lately.