Rough Idle

skeeattle · #1 10-23-2010, 03:21 PM

2003 x5 4.4 113,000. I know there are lots of threads on this but I cant find any answers.
Can anyone give me a suggestion as to why, at Idle, cold or warmed up I am getting a rough Idle, it is intermittent but mostly rough idle 90% of the time, the RPM gauge is a slight tick above 500rpm while in drive. I put in techron and it seemed to help a little, I also put in some of the bg44k stuff in, didnt seem to help. I cleaned the MAF, no help. I am thinking about replacing the MAF. I Cleaned the Throttle body, it maybe helped a little. Newer plugs and Fuel Filter.
Also, I think this may be related--When I decelerate at higher speeds, the car seems to shake or vibrate upon heavy deceleration, like it is catching up with the transmission and I can feel it more if the road is smoother and level. Fuel injector issue? I am fairly confident it is not the tranny (had 2 shops look at it (BMW and Indy) and they changed the Tranny fluid). Maybe have the transfer case fluid changed?
It also feels a little sluggish and sounds a little loud and (maybe a little whine) under heavier loads. I use premium unleaded only from Costco-I know not the best but not the worst fuel.
I dont want to pay over $100 to have it diagnosed and them replace things it may not be.
If it is vacuum related can anyone point me to Real OEM as to where the vaccum lines are? I cant see that there is a ICV in the 4.4's model year 5/2003? There is no oil separator am I correct?
Oh.. and there are NO CODES.
Any help would be appreciated.

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X5driver214 · #2 10-28-2010, 04:10 AM

Check your engine mounts, I had similar problem where my car would vibrate while in gear at a stop, I replaced the engine mounts and it was smooth again.

Wayne's World · #3 10-29-2010, 09:39 PM

Quote:

Originally Posted by X5driver214

Check your engine mounts, I had similar problem where my car would vibrate while in gear at a stop, I replaced the engine mounts and it was smooth again.

I have experienced the same issue in an old E36. The deceleration symptom sounds like your engine mounts. I've driven an E36 without ANY engine mounts installed so I know exactly what the worst case scenario is. If you've cleaned the throttle body, did you also clean the Idle Air Control valve? Also a tip I picked up is to put some white lithium grease around the sealing surface of the nipple of the IAC - the area that you're going to shove into the vacuum hose under the manifold when you reinstall it. It helps to slip it in easy and form an air-tight seal.

Wayne's World · #4 10-29-2010, 09:40 PM

Also, SeaFoam does wonders for rough idle! Cheap and quick.

mywidebody02 · #5 10-29-2010, 10:53 PM

check your crank ventilation hoses under the cover towards the back. There are 2 and make sure they are not mushy and soft.

skeeattle · #6 10-29-2010, 11:10 PM

Thanks,
I ordered a new MAF Sensor and it should be here next week and I will check the Motor mounts and ICV this weekend, and keep you posted.

Wayne's World · #7 10-29-2010, 11:42 PM

Keep the receipt handy. Faulty MAF sensor typically throws codes.

matt1mike1 · #8 06-13-2011, 06:00 PM

Did you figure out what was the cause of the rough idle?

skeeattle · #9 06-14-2011, 10:34 AM

No, but I think changing fuel helped. I switched to Shell and 76, from costco gas. I have put Techron in, Bgk 44 and all all types of additives in thinking it may be a Fuel injector. (no codes though) I was going to change the knock sensor, but havent gotten around to it yet. I get some ping/knock when in drive, under a load (like giving it gas starting to go up a hill). I assume you have the same rough idle issue? What have you done to trouble shoot?

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