Idle and fan problems - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

tdpower · 11-20-2009, 08:22

I have a 2001 mustang with a 3.8 v6. My fan is kicking on and off when the engine is cold. Also, my idle is at times fluctuating down and lot more than normal. I was thinking the IAC and maybe the coolant temp sendor? Not getting a check engine light so don't think there are any codes. Any thoughts?

**Bert** · 11-20-2009, 08:30

There still could be codes. Do you have the defrost on when it does this? maybe the A/C compressor is cycling.

tdpower · 11-20-2009, 08:37

Thanks for the quick reply. I will take it over to autozone and see if there any codes. I did notice the ac compressor did kick on. Not sure if I had it on defrost though. Seems wierd for the electric fan to be kicking on when the engine is cold.

tdpower · 11-20-2009, 09:10

Just went out and checked it out again. Getting a cold start issue as well. I replaced the battery a few days ago for the cold start issue and thought it was fixed. Alternator charging above 14vdc and cables look good. I replaced the spark plugs a couple of days ago chasing a drop off in fuel mileage. I guess I will replace the spark plug wires and the electronic ignition module (not sure what it is called). With the fan switch in the off position the electric fan in the engine does not come on so maybe not a problem. It did come on after I turned it to defrost and saw the ac compressor cycle after a little bit.

**Bert** · 11-20-2009, 09:10

Anytime it senses freon pressure, the fan will come on. The A/C compressor comes on with defrost to dehumidify the air.

tdpower · 11-20-2009, 09:21

I thought the fan would only come on after the engine was warm and to keep from overheating. Guess I was thinking wrong. I will get some spark plugs wires, module, and scan for codes. Thanks

**Bert** · 11-20-2009, 09:52

Get some MAF cleaner and clean the MAF. Also clen the ISC. Idle speed control.

tdpower · 11-20-2009, 10:45

I did clean the IAC. Is that the same thing as the ISC? I will clean the MAF. I do have an aftermarket cold air intake and sensor but never had any problem. Car seems to idle ok if not in the defrost position. Still not bad in defrost but seems different from what I remember in the last couple of years. Right now I think I am troubleshooting a cold start issue and poor fuel economy. I was thinking a basic tune-up would be good for starters.

**Bert** · 11-20-2009, 11:26

Depending on the cold air intake, you can get a coated MAF. The IAC is the same as ISC.

tdpower · 11-20-2009, 11:53

Went to autozone and not pulling any codes. Got some spark plug wires and some fuel cleaner so hopefully that will fix it. Also, will try to clean the MAF sensor. Bert, thanks for the help.