BloodTypeOctne

At my shop we've had two 2000 Mercury Grand Marquis LS's come in with code PO1507 IAC Underspeed Error and a complaint of either a no start or stall in the morning when the engines cold. One car has about 54k and the other with about 110k on the odo. One owner couldn't leave the car, but one did. Next morning start it up, no problem. It did idle a little rough, my assumption because of how long the car sat, plus it was about 40F out. But the weird thing is every test we give the IAC it passes no prob and we can't replicate the problem, even if we let the car sit all day. My boss also heard that these are becoming more common. Anyone know if there's any TSBs or any word from Ford about this problem?

Johnny Mullet

We have actually encountered two Crown Vics with this problem and are unable to fix them at our dealership. I am sure we will figure out the problem sometime since the one owner left it for a week. One is a 1999 and the other is a 1996 model.

BloodTypeOctne

Yea we dont have Alldata at my shop (Which I can't stand) and couldnt see if there were any TSBs out for it. The guy actually came in the other day and brought it to the dealer, their replacing the IAC, which pisses me and my boss off cause we were gonna do it, but every test we gave it with the Vantage passed. And we didnt wanna charge the customer the money for the part if it didnt fix it. I think net is an upwards of around $125.

BloodTypeOctne

Thanks for the info, now that I know its going around to the 4.6s. Which I have to keep an eye on since I have a 97 Town Car, but I know my IAC needs to be replaced, I just dont wanna since Im getting a new car soon. Let me know if its deffinitly the IAC causing these problems.