Rough Idle, maybe normal?
#1
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I will admit since the Pandemic the 2010 XF Supercharged is not being driven as much as usual. As of late it has been cold outside temperature wise. I am wondering during engine warm up say 15 to 20 minutes if some rough idle is normal? There are no check lights coming on, just a small erratic jump in RPMs from time to time. To my understanding the 5.0 Supercharged engines aren't the smoothest during warm up, and it takes some time to get the V8 properly warm.
#2
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#4
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Like NB cat says, check your STFTs and LTFTs, I had a faulty MAF that gave readings with range but not actually related to the amount of air going in, and a gummed up throttle body which seemed to give a slightly rough idle and weird RPM lag and jump at about 4000rpm.
I kind of tinkered with it trying to work out what was up, it went into the garage a few times before we found the MAF fault. However by then it had destroyed the cats with unspent fuel being thrown in there.
You should also check your coil pack and check the sparks to see if any oil is getting in to any of the cylinders from the cam cover.
I kind of tinkered with it trying to work out what was up, it went into the garage a few times before we found the MAF fault. However by then it had destroyed the cats with unspent fuel being thrown in there.
You should also check your coil pack and check the sparks to see if any oil is getting in to any of the cylinders from the cam cover.
#5
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After a can of BG44K, and some more consistent driving, the problem seems to be clearing up. At this point I am convinced it may have been dirty injectors, or old/bad fuel in the tank. If the issue returns I will further investigate. I am definitely going to give the car more drive time. It has been sitting far too much this year.
#6
![Default](/forum/images/icons/icon1.gif)
After a can of BG44K, and some more consistent driving, the problem seems to be clearing up. At this point I am convinced it may have been dirty injectors, or old/bad fuel in the tank. If the issue returns I will further investigate. I am definitely going to give the car more drive time. It has been sitting far too much this year.
#7
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The rough idle condition returned. After further investigation I believe I found the source of the issue. The cold air intake tube/hose was cracked completely through, right where it seats to the throttle body. It also pulled the vacuum hose from the supercharger loose as well at the intake tube. I couldn't see the issue until I removed the clamp at the throttle body, completely cracked dumping air everywhere. New intake tube on order from Mina Performance.
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NBCat (12-31-2020)
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