Car is dying while slowing down....what's broken?
 

My 00 SE w/ about 100K on it has always had a weird idle when slowing down. It will dip real low as I'm on the brakes almost to a complete stop for a second, then go back to normal. If it usually idles around 1100 RPMs, it dips to about 800 for just a second, then goes back up. Its actually kind of annoying because it happens everytime I'm pulling in my garage and when the idle drops, the power steering gets hard to use for a second.

Lately its getting worse - for about the last two weeks when the RPMs would dip, the car actually dies here and there. I was pulling in to a parking spot today and the car just died. It was kind of dangerous because I suddenly lost power steering and brakes. It usually happens as I pull in a parking spot or to a stop sign - but today it happened as I was getting on an entrance ramp too. Its also hard to start it again - it will start up but dies if I don't keep on the gas for a few seconds. On the entrance ramp today I was already going about 40 - so I just put it in third and popped the clutch.

What the hell is broken? I'm getting ready to call my mechanic right now.

I had similar ssues with an older mustang - turned out to be a weak battery or bad ground connection which really impacted idle. With all the sensors etc, the batt power/connection plays a big role. Is it the original battery? Wouldn't hurt to give the connections a good cleaning. Pulling any codes from the computer?

I had a similar problem with my max last summer, it turned out to be a bad alternator, or it was the MAF.. i can't quite remember. One time my car stopped while turning left in a busy intersection.. luckily the car restarted on one try.. but it was close! Get that checked out immediately..

I believe it may be the battery I am having similar problems and its about that time for a new battery

I think its MAF, had the same problem, replaced it and no prob..

At 100K miles, change the MAF, and while you're at it, clean the throttle body.

I would say clean the throttle body and if that doesn't fix the problem (which it did for me) then replace the MAF

Thanks for the feedback guys - I'll start with checking the battery terminals and throttle bodies. Do we have a write up on the throttle bodies anywhere?

Battery - is an Optima red top I got about two and a half years ago - should I have it tested as well as cleaning the terminals?

MAF - any way to test it before I go and buy a new one? Where do I get one - Dave B? How much?

One thing to note - it happened to me several times this morning, but then never again after a highway trip of about 80 miles. After the highway trip I drove about 30 stop and go city miles. Perhaps only when its cold????

Also - I have a code here and there for my second O2 sensor. I always just reset it and assume its my RT Cat that does that. Could this affect it at all? I've had the cat for almost two years.

That battery should still be good if its a red top. Steel brush your terminals

your problem is not battery related that is for sure. Two things i would check are MAF of the IACV

How can you troubleshoot the IACV?