1996 Grand Marquis stalls when cold

[rapleyan]

I have a 1996 Grand Marquis. If the car is cold-started in temperatures below about -10C/14F, it will often stall when I first put it into gear. Seemingly the engine can't hold its idle with the extra load of having the transmission in gear. After stalling, there is usually a very long crank to get the engine started again.

Once the engine has warmed up a bit I do not experience this problem. I can even turn off and restart the warm engine without problems.

I took the car in to the shop for diagnostics. No computer error codes were detected and the fuel pressure was good. The technicians cleaned the throttle body assembly and flushed the injectors.

Apparently problems of this nature on several Ford vehicles can be caused by a defective idle air control (IAC) motor. I replaced this unit on my car, but the stalling issue persists.

Would anyone be able to offer any insight on this problem?

- Tony

[fredjacksonsan]

When it's colder, the transmission fluid is much more viscous, so makes more resistance inside the torque converter. I'd be inclined to just let it warm up for an additional 30 sec to a minute, and see if that takes care of it.

[rapleyan]

I don't think an extra 30-60 seconds of warm up time will help in this case. I can let the car sit and warm up for 10 minutes or more and I will still experience the same problem. I also think the long crank after a stall would seem to point to some sort of engine management problem rather than a transmission problem.

[fredjacksonsan]

Yep, I agree with you and it seems there's something odd in the startup circuit. I take it your MGM is in a good state of tune (plugs, wires, air filter etc). I wouldn't rule out a vacuum leak somewhere either. The hard start is an odd condition also. There is a post here in this forum about a pollution control part that caused some cold startup problems but I don't recall which one it is; if I come across it I'll put the link in here.

[rapleyan]

Yes, my car is in a good state of tune. What about the MAF sensor? Are you or anybody else familiar with the symptoms of a bad MAF on a Grand Marquis?

[fredjacksonsan]

I've heard that a bad MAF can cause lots of odd problems, so that could be it.

But rather than throw a bunch of parts at it, it might be a good idea to plug it in to a diagnostic computer....

[rapleyan]

I've heard the same thing about the MAF, and I'm also in full agreement that it's not the best idea to start throwing new (expensive) parts at the problem. I'll see if there's a mechanic who can perform a diagnostic on the MAF itself, given that no error codes were being stored in the computer.

[windsoron]

Originally Posted by rapleyan

I've heard the same thing about the MAF, and I'm also in full agreement that it's not the best idea to start throwing new (expensive) parts at the problem. I'll see if there's a mechanic who can perform a diagnostic on the MAF itself, given that no error codes were being stored in the computer.

You can clean MAF easily without taking your car to shop. You may or may not know Crown Victoria forum: pls check http://www.crownvic.net/tech/cleanmaf.html

Another suggestion: Try synthetic ATF (MERCON V), that may help as well.

Good Luck