crusininda944

So tonight when I was out, the car suddenly developed a rough idle and now stalls when I come to a stop.

Additionally, when I was on the highway, if i let off the throttle just a bit, the car kicked back and shuddered. When I gave just a bit of throttle, the car lurched forward and then lurched back and the gearshift would be very rough.

I'm going to take a look at it in the morning, but what should I check to address this issue? I'm going to clean the MAF sensor, but I don't know where anything else under the engine is, or what should be checked.

ricoblanco

Check your vacuum lines.

Audiolic

IAC failure was IDed. Just buy one from the site A6Gary recommended. Let us know how it goes..

crusininda944

Today, when I started the car up, it was a bit shaky and when I was doing a 3point turn to maneuver it into the garage, it seemed like it was getting ready to cough out at low throttle.

Once in the garage though, it seemed to stable out.

After letting it warm up, I revved it for a couple of minutes to the redline back and forth and let it idle.

Afterwards, it idled for 10 minutes without choking and I turned it off.

Audiolic

$185....But it seems their transaction server is not encrypted when you check out...


Your car will behave as you described but the prob will not go away until you are sicken tired of doing all the manuvers with it and then replace the IAC...

Audiolic

waht is the milage on your car and what is your normal idle speed ?

crusininda944

Could it just be a dirty idle air controller? Before the issue happened, I drove a full tank (330 miles) to Erie, PA from PGH and in erie, it was snowy/gross and I had to drive on a paved road with dirt covering it. Could the valve just be dirty causing this issue?

The car drove absolutely fine in erie which was about 120 miles from my house, and all day in erie it didn't have this issue. It wasn't until on my way home, after driving with the dirt did it happen and begin idling very rough.

I put about 10 gals of premium and some seafoam in the tank and the power seemed to come back a bit, but the idle is still rough.

Audiolic

you need to get a new IAC. Beep-beep and v b chil-n had some great posts on how to clean the IAC.

I had a rough idle and the fuel economy was really bad. My car was only getting like 15mpg on highways. I had tried to clean the IAC but it didn't improve much. Further OBD starts throwing DTC 1504. After much troubleshooting, replacing TB gaskets, hoses, MAF cleaning, smoke test...you name it, I finally replaced IAC and the car runs ok now. Why I don't say it runs great? Because it seems the IAC I got from online retailer auto hausaz has lower quality than what you would get from dealers.
My NEW IAC idles normally around 800, but occasionally it dips to 650~ 700 range, which makes the car shudder a bit. But otherwise it is ok, at least there is no more DTC codes and fuel economy is back to 21 mpg highway.
I guess you get what you paid for. It seems to me that the dealerships get parts with highest quality. You can get a cheapo from online retailers or get a quality one from dealers with higher price. Regrettably speaking, I didn't know the difference in quality before I ordered the IAC from online because it was about $150 cheaper...

crusininda944

Burnt through the rest of the can of seafoam driving 15 miles at autobahn speeds. Luckily there was light traffic going into the city today, woot!

The car is dramatically different. I got off at 3 exits and she didn't idle rough or stall once.

I even got to roll with a classic 328 Ferrari and new CLS which were both trailing/leapfrogging me.

I've never had so much fun reconciling a car problem before. Hahah.


On a side note, my vaccum lines looked pretty crusty as well. I think I'm going to be replacing those in the future to prevent any other problems.

Thanks for your help guys.

Audiolic

Very nice....:O)