I think I have two issues. My 96 w a 4.0l had always surged at idle. Sometimes you though it was going to stall but never did. Mechanic once told me that was the electronic distributor I have in it made it do that. Never understood that since my 94 does w/ a 4.0 l never did that. That surging never bothered anything until recently when the check engine light came on. Now I have an egr code and it does stall occasionally when at a stop sign. I have repaced the egr valve in this unit twice in the last 4 years and most recently have replaced the MAP (Manifold absolute pressure) 6 months ago. For the past 6 months besides the surging idle the check engine light has stayed out and it has not stalled until the check engine light came on last week with the EGR code. Again the surging does not bother me but that combined with the new problem just seems to be too much for it and it stalls. Daughter is driving it and this morning I had to teach her how to drive two footed. She is freaking with that. Any ideas?

 

Hi Ehawks:

First, welcome to our FTE Forum

I'm almost certain it's the Idle Air Control Valve if it's surging. It's easy to change.

 

yeap IAC for sure - the surging is a dead giveaway - Try cleaning it all out first and spray out your TB too with a good cleaner... you will notice the difference in stop and go driving.

what code are you getting? it could be 2 problems. How does it run once it's warmed up?

 

I found that the idle control valve is the common cause for this problem. Easy fix and cost for part less that 50 dollars.

 

My 95 was a vaccum leak. Could be that.

 

not usually for the surge, but could be causing the rough idle. - where was yours?

 

Mine was up at the manifold. It was causing the van to wanna idle rough as well as jumping ahead at stop lights and that. However when it was under throttle it was fine.

 

I installed the Idle air valve and no difference. No biggie, the van has 210,000 on it and it was original. Still surging but I think what is important to identify is the symptom. I said surging, perhaps it is less surging and more rough idle. Basically is runs rough at idle and sometimes it is like the ignitrion cuts out for a split second and then kicks in again. That is where the surge comes in becuase the engine then speeds up and then settles down again. This is constant and it can never find a good idle rpm. It even has trouble staying constant when running at 250 hundered rpm when manualy holding down the throttle. You can hear it stumbling a bit although this never translated to bad gas mileage or rough running at highway speeds. I have had it for 7 years and got it with 150,000 on, since then have replaced both head gaskets, two egr valves and and it still and always has done it. Most recently it has gotten worse at idle and has occasionally stalled at stop signs. Coincidently the check engine light has come on and i get a code of P1443 which is egr control valve. I had parked it most of the summer and just recently started driving it again. perhaps the egr valve is stuck? I was dinking around with it the other day and noticed that when at idle I couild talke the hose on or off the egr valve and no difference. also did that while at 2500 rpm, again no difference. That is where I am at, any other ideas?

 

Clean the EGR Valve, and hoses... if you are getting an EGR code, that is a good sign, since the whole system is less than $150 to redo, if you have to, with new hoses, new valve, sensor, etc...

if you suck on the hose while off, (sounds insulting :-)) does it change the idle?

Keep us posted - I'd love to find out what's going on there...

 

also check for burned thru hole in EGR tube to exhaust manifold...or hole in line that feeds exhaust fumes to intake...or failed leaking burned thru EGR gasket....or leadking fitting at EGR connection to exhaust manifold
something is feeding in extra unmetered oxygen loaded air into intake.....hot run normal EGR system only should feed in exhaust gases which have almost no oxygen and simply displace normal oxy air mix.....injected exhaust gases lower combustion temps in comb. chamber thus lower NO emissions...also cut horsepower

 

Ehawks,

The EGR system usually only activates when the engine is under load, as in high manifold pressure (low vacuum). As someone suggested, use a vacuum pump and pull some vacuum on the EGR valve while the engine is idling. It should stall the engine. This shows that at least the EGR valve will respond to vacuum. I'm not sure how it's configured on the 4L engine, as I do not have one on mine, but if you can remove it, and plug up its opennings, you can eliminate it as the source of your surging.

Have you tried to find a vacuum leak yet? The big one on mine was on a vacuum tree at the rear of the driver's side of the intake manifold. You can get to it from the dog house openning inside, but it is near the very left edge. Feel around it for open ports or loose hoses. Whenever one of mine pops off, the engine will stumble and surge as you describe, and sometime will trigger the CEL.

 

thanks for all the great advice. i won't be able to act on this as I am flying out to NJ to visit friends and purchase my buddy's 97 Aerostar. they have had it since new and it has no rust and 130,000 miles. Just broken in. Don't know what the dealer offered them for it on trade but couldn't be much as they are selling it to me for $500. I will take all your advice and check the old dog out when I get back. If that does not get it perhaps I'll drive it to the junk yard.

 

a 97 for $500 - drooling - all my friends make fun of me for driving a OLD minivan, until they break down and need a ride - LOL!

 

ehawks:

Don't dive the old dog to the junk yard..kept it around for parts.
No need to have to buy the parts back when you need them, if the van stays at the junk yard long enough.

Jay

 

Finally had some time to dive into this. I did everyting you guys told me to and everything checked out......I had one last vacuum hose that I was tracing back under the air cleaner (to look for a leak) and needed to remove the air cleaner houseing to get at it. Upon removing the air cleaner I noticed that some leaves and nuts fell out of the intake. BINGO. They it hit me. I had parked the van for a few months last spring and when I fired it up I saw a couple of flashes flying out of the front of the Aerostar but just figured it was some stupid chimpmonk and oh, well they just lost their home. We the van ran ok but apparantly over time the air filter just kept sucking more and more of those leaves into it till it got to the point were a combination of the colder temps and the blockage the van just could not run right any more. $5.00 at Autozone for a new filter and I am back in business. Guess I'll put a screen on the intake to the air cleaners on all the aerostarts now!
Thansk for your tips.