2002 2.0 Zetec Ford Focus.
Here are a few issues this poor car has:
PCV hose flattened (filter most likely bad too)
Valve cover drenched in oil (of course it is with a bad pcv)
Second oxygen sensor wire FELL OFF the sensor when I LOOKED at it funny. By the state of the second sensor, lets assume the first one is bad too.
The car runs like an absolute TOP…until it warms up. Upon reaching a warmer state it drops rpms and stalls.
Which of these issues is the most likely culprit of the stalling? I already fixed an irregular idle by cleaning the MAF.
The problem might be a bad Idle Air Control valve.
To find out, start the engine and let it idle until it starts to drop in RPM’s. Then slightly step on the gas pedal.
If doing this prevents the idle from dropping and the engine from stalling, it points to the IAC valve as the being the problem.
Stomping on the gas does, if I’m fast enough, recover from stalling until it drops back down to idle. Sometimes this takes a few seconds before I get a response. Can the IAC valve be cleaned, or should I just replace it?
You can try cleaning the IAC valve and throttle body. But I’ve never had much success cleaning Ford IAC valves.
Thank you for your help, I’ve been trying to tackle the stalling before I move on to the other issues.