Possible Vacuum Leak Problem

I have a 2000 Explorer XLS. Over the last month or so a problem has developed on a cold start. The engine starts immediately, as normal, and begins to idle at about 1500 rpm, as normal, but then after 2 to 3 seconds the rpm begins to drop fairly drastically and at about 500 rpm the engine begins to sputter and cough, then will die unless I quickly press the accelerator and boost the rpm back up. After the engine begins to warm up, it's able to keep going on its own. No trouble code lights or check engine lights appear at any point.

I recently got new plugs and wires, a new fuel filter, and had the injectors cleaned, but that helped very little if at all.

I think this might be a vacuum leak problem. It's much worse on cold mornings. It goes away after the engine starts to warm up. And no problem at all on a warm start.

Does anyone have an idea?

Thank you
biullybw

I suspect the IAC valve. Have you cleaned it?
They get "sticky" inside.

I had the exact same problem last winter when it started getting cold. I replaced the IAC and it fixed it. I started getting the problem again this year, and was wondering if it was possible that my IAC was going bad. I got a CEL and the codes were bank 1 & 2 lean. The first thing I did was have my mass airflow sensor cleaned, and it has totally fixed the problem. So, if I were you, Id either try to clean the IAC or Id really recommend getting a new one, and also try cleaning your mass airflow sensor. Good luck.

Thanks for the quick replies. I'm really not a mechanic, so I'll have to get a repair shop to replace the IAC valve. But would I be able to clean the airflow sensor myself? Or should I maybe just get new one put in?

Thank you

billybw said:

Thanks for the quick replies. I'm really not a mechanic, so I'll have to get a repair shop to replace the IAC valve. But would I be able to clean the airflow sensor myself? Or should I maybe just get new one put in?

Thank you

Click to expand...

You can do both yourself---It will take more time to schedule the appointment.
You should find all the answers through searching this site.

maf link
http://www.explorerforum.com/forums/showthread.php?t=154711

do both urself like jtsmith said, it's only a couple screws

Thanks for the replies and the advice. I'm still afraid to try this myself. I looked at the article and it said I would need to buy special tools just to get the MAF out. also would have to disconnect various wires etc. I don't think I can do it.

Explorer Maintenance

http://www.explorerforum.com/forums/...6&page=1&pp=20

Explorer MAF cleaning

http://www.explorerforum.com/forums/...=cleaning+mafs

IAC Cleaning:

http://www.explorerforum.com/forums/...&highlight=iac

And, another IAC Cleaning thread:

http://www.moddedmustangs.com/cleaning-your-iac.html


And Vacuum testing gauge:

http://www.gregsengine.com/vacuum.htm


Aloha, Mark

although everyone elses ideas are solid.. i don't think they will solve your problem. i had the same problem for 3 years and never could figure it out. after much research on the board i realized it was the intake manifold gaskets and the "O" rings..

the exact problem was a recall if you had less than 75k miles i believe.. the recall is the 00m12 recall. you can search for 00m12 for more details. the whole procedure at my local Ford dealership was right around 200$. I have learned, though, that many other people have tried to get an estimate and the estimate for the 00m12 recall was MUCH more than 200$ for them - why i don't know.

I'm guessing you will get an estimate anywhere from 300-500$ to fix this.

For more details..
http://www.explorerforum.com/forums/showpost.php?p=487634&postcount=33

i have that problem had it for about 3 years now i fixed iac but it still reads the lean code bank 1 and 2 and check engine light is on also i have a k&n cold air intake i thought that could be the problem but i put the stock back in and the same thing happened maybe i should try to clean the mass airflow sensor or get new manifold gaskets?

i'm telling you guys.. get the 00m12 recall fixed.. intake manifold gaskets (O-Rings).. a cam chain tensioner is also included in the parts .. call ford and ask them about it and get a quote. it will solve your problems like it solved mine.. stop wasting money on the other stuff

ok ill try that thanks

Thanks for all the new replies, although from what I'm reading it doesn't look like this will be a quick or easy or cheap fix. But before I make a decision about what to do, I would like to ask one more question:

Does the fact that this problem apparently only occurs in cold weather on a cold start give a clue as to its most likely cause?

Thank you
billybw

yes the cold weather shrinks the O-rings which allows too much air to pass through them which causes your rough idle. i'm no mechanic but that's my knowledge of it. when your engine warms up those O-rings expand and stop the air which brings it back to a somewhat normal idle. if you get replacement O-Rings they won't be worn out and shrivled in cold weather and your problem is gone. it's not a simple easy fix but it took my ford dealership here 2 hours to fix it. if they tell you it takes longer they are either idiots or just trying to rip you for more money..

this is the main problem. you can fix your IAC but the problem won't go away without fixing the O-Rings in the intake manifold gaskets.. i'm noticing some slight idle roughness right now but it's because my IAC is going bad. it doesn't try to cut itself off like it used to.. just a little vibration at times. if all your truck does is vibrate a little at idle it's probably your IAC. you can get a new one from ford for like 115$.. and it's a simple install - anyone could do it

Just wanted to let everyone know that replacing the o-rings has apparently completely solved the problem.

I got the job done at National Auto Parts for about $250.

Thanks again to everyone for your help. You have saved me a lot of time and worry.

billybw