We have a 93 Aerostar, 6 cyl. auto, AWD, 130,000 miles.

Recently it has been idling a little rough when cold, but would be OK once warmed up. Yesterday, all HE** broke loose when I went to drive home from work.

First - It would crank over to start, idle real fast for a few seconds, then when it would normally drop back to regular idle, it would just shut off. It did this repeatedly. I found by pressing the accelerator, I could keep it running, but roughly. I sat for at least ten minutes forcing it to run, waiting for the dial to indicate it was warming up. Once it warmed up some, it would still shut off, but I could keep it running by giving it the gas. I had no alternative but to attempt to drive home this way. I did get it to drive, roughly, by never letting my foot off the gas, it would go about 35 mph. After about 1/2 mile, the "engine" light came on and stayed on, but I did make it home, about 5 miles. Today, it is same thing - starts fine, runs a few seconds, then boom - shuts off.
My husband knows how to work on older vehicles, but this is first fuel-injected one we have. We read in a book about listening for the little fuel pump motor, and we can hear it run when we turn over the key.
Any ideas what we should be checking on this thing?

Thank you!

 

From your description, it sounds like the culprit is the Idle Air Control (IAC) valve, located on the throttle body. It is easy to remove and clean with carb/choke cleaner. Usually this solves the problem but occasionally one does require changing out.

There are many posts on this board, several almost word for word with your description. Try using the search button at the top of the page for further reading. (You need a minimum of four letters in each word, so type IDLE CONTROL VALVE instead of IAC)

Good luck!

 

As aerocolorado pointed out, the IAC is a prime suspect and deserves to be inspected and cleaned at the very least, especially if it hasn't ever been done. However, you should pull the code(s). Some auto parts stores will do it for free because they're hoping to sell you a part. In addition to having a clean IAC, the idle needs to be set properly. If it was running rough and backfired, one or more of the vacuum hoses may have been blown off as well contributing to rough running, so give them a good inspection too.

Did you notice any other symptoms, such as black smoke, any difference with the transmission in nuetral?

 

I drove an aerostar that had the same problem was fixed for around $50- and it ran like new. Good luck

 

OK, Ghostgunn, are you going to keep us (or at least me, anyways) in suspense and not tell us (me) what the $50 fix was?

 

Sorry, I was agreeing it was the IAC, forgot to explain . WHen they go bad all sorts of running /not running problems jump up the simple fix cures it perfectly. Good luck..

 

My 92 4.0L was running poorly when cold also, somewhere on this forum I found a thread about cleaning the MAF sensor. I used 1/2 a can of carb cleaner on it and now it runs great...

HTH, Robert

 

It could be the fuel pressure regulator. If the diaphgram leaks just a little bit, it might not be enough to cause a lot of black smoke but it will cause rough idle when engine warms up.

 

UPDATE -

OK, after $800.00 it now runs again, but the idle is still crazy.
We replaced:
Plugs & wires
EGO
IAC
MAF
TPS
a leaky flex-pipe by the muffler.


It runs pretty good now, but it idles too fast. After driving awhile, if I stop & put in park, it really races, and I have to floor it & let up, then idle finally comes down. It is also idling too fast in drive, feels like it wants to drag me through the red lights !

Any other suggestions? This is getting very expensive !!!