Wouldn't start, then cut out when running

[MJOR]

So my sister's home for the holidays and I decided I'd be a good brother and get some things fixed on her car and lend her the Marauder for the mean time. Turns out that my car is the one that needs the TLC...

She called me today saying the car wouldn't start. At first nothing happened when she turned the key (no noise, didn't turn over), then later she tried again and it started for a couple seconds and cut out. Then she called me and went back out to the car, and again she turned the key and nothing happened. Voltmeter is at 12 and drops below 10 when the key is turned (seems normal to me). Then I tell her to put it in neutral and try it, and it starts right up (Voltmeter at 14-15 when running). But it seems that this is just a coincidence because 10 minutes later she calls me back and says that it stalled while driving it down the road.

So the first thought that jumps to my mind now is, "what have I done to the car?" since I bought it:
1. Lidio XCal3 tune - did this a few weeks ago and it has been running beautifully ever since
2. K&N filter W/ INTAKE KIT - Ran beautifully for a few days, but then I gave the car to my sister yesterday and she's having problems with it after one day. Also, two days ago I drove it in fairly heavy rain. So my thought is dirty MAF from on over-oiled and possibly wet filter? She didn't put any gas in it or do anything but drive it around. If it is the MAF, what stops this from happening again - does anyone else have problems with the K&N kit?

[MJOR]

One more note, when I say over-oiled filter, I mean possibly over-oiled out of the box. I didn't add any oil to it.

[sd8683]

Clean your MAF and work from there

[sd8683]

Could be a vacuum leak.

[MJOR]

Yeah, thanks - sorry for the long explanation, I'm just pi$$ed that my car broke down for the first person who borrowed it since I bought it (less than 2 months ago)! I'll try cleaning the MAF and see if it goes away.

And I just saw that the Drycharger air filter cover was recommended (in the Review section) for the K&N. Maybe a lot of water just gets to the filters in these cars.

[MJOR]

Now I looked at the car myself. It cuts out when you hit the brake! The first few times I turned the key, it started right up, then when I put the brake on to shift out of park the engine died. My sister said the same thing happened when she was driving down the street, the engine cut off as soon as she touched the brake pedal. This seems like an electrical issue, but with what?

[Aren Jay]

.............................. .......

[MJOR]

I took it for a drive, and it cut out on me. The stereo lights and everything went dim first, so I figured the battery idea is the most likely solution and went ahead and replaced the battery. But now it's still doing it and the voltage when running is 14-15 volts so I don't think it's charging system - does a K&N intake void an extended warranty? should I put the stock intake back before towing it to the dealer?

[sd8683]

Check your alternater.

[MJOR]

So the dealer says that it's my Idle Air Control Motor which is a little under $400 including labor (covered under warranty though). This started happening a few days after installing the K&N, could this be related somehow? I just don't want it to happen again because it's not covered under my extended warranty, they're just doing it now because I just bought the car.

[larryo340]

So the dealer says that it's my Idle Air Control Motor which is a little under $400 including labor (covered under warranty though). This started happening a few days after installing the K&N, could this be related somehow? I just don't want it to happen again because it's not covered under my extended warranty, they're just doing it now because I just bought the car.

Very easy to replace, and at rockauto.com the Ford IAC is reasonable:

MOTORCRAFT Part # CX1781 http://www.rockauto.com/catalog/images/MoreInfo.gif {#1S7Z9F715CA}
1S7E-9F715CA* Non-stock item--shipping delayed up to 2 business dayshttp://info.rockauto.com/getimage/getimage.php?imagekey=382752&imageurl=http%3A//info.rockauto.com/Motorcraft/CX1781.jpg
$74.79

[MJOR]

So Muzi Ford (Needham, MA) finally "tracked down my problem" to the main wiring harness after replacing the IAC and some other harness without fixing anything. It's being replaced under my extended BaseCare warranty which is also covering my rental thankfully.

Has anyone else had electrical issues like this on a car with 50k mileage?

[wchain]

It wasnt rubbing at that spot against the firewall that some 300A Cars had problems with, was it?

http://www.mercurymarauder.net/forums/showthread.php?t=2454&highlight=wiring+harness+chafi ng

[Dragcity]

I stuffed a section of a 1 inch rubber heater hose between the harness and the SHARP steel bracket that lives directly above it. Did that the first week I had the car. Looked like a potential problem from the get-go...

86,000 mi and still there.

[MJOR]

Thanks for the tip! I'll be sure to go over everything when I get it back.

I'm not sure where my problem was. One service writer told me it was a chafed wire by the front bumper and that the wiring harness would be here Tuesday. Then I was called on Monday and told it was the main wiring harness that would be here Thursday. I'll find out when I pick it up.