Engine stops when hot. Please Help

[nola]

I am hoping you guys can help me out. I have a Ford 96 XLT Explorer. I have been having these problems for quite a while now and would like to get some idea of what is causing it. I probably will have some shop fix it but I want to get your opinion on this before I go to them with absolutely no knowledge of what is going on.

The first problem seems to occur when the temperature/weather is hot and only after I have been driving the car for a while (doing errands, etc). I will start the engine and get normal idling RPM while the transmission is in Park. As soon as I shift gear to Drive, the RPM drops and engine dies. When I put the gear back to Park to start the engine, I get normal idling again but as soon as I shift gears again, same thing would happen. I can still drive the Explorer while experiencing this problem but I will have to step on the gas lightly while shifting gears and stepping on the brakes all at the same time. During these episodes, the engine seems to labor a little bit more.

The second problem may be related but I wouldn't really know. Again, these occur when the temperature is hot and only after driving the Explorer for a while. The Explorer will start to emit a strong humming sound while the engine is running but not moving (it may also be happening when the Explorer is moving but it is not obvious and seems to die down or be drowned by engine). The strong humming sound can be heard regardless of what gear I am on (like on Drive during stop and go traffic)

In both these problems, the problem seems to go away temporarily when I start the engine in the morning while the temperature of both engine and outside weather is still cool. The problem typically comes back later in the day.

Please help and tell me what to look for.

Thanks.
Nola

 

[Jason_25]

The solution to both your problems is likely the IAC valve. It's about 100 bucks and is very easy to change.

 

[nola]

Thanks for the quick reply. I will have the IAC checked, cleaned or replace. I have also spent the last couple of hours looking at the threads here and I found a few discussions suggesting a possible "02 Sensor" problem. Would the 02 sensor also be relevant.

 

[TPLYNCH]

Usually if you have a bad O2 sensor, your CEL will light up. I agree with Jason. Sounds like a definite case of bad IAC. If you try removing the airbox while the humming is occuring, it will get louder if it's the IAC. As for the idle problem, is it any better or worse if you have the A/C on or off?