Rough idle, exhaust smells like gas, after timing chain job 2005 4.0 | Ford Explorer Forums - Serious Explorations

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Rough idle, exhaust smells like gas, after timing chain job 2005 4.0

d73805

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Joined
November 19, 2011
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City, State
Long Island, NY
Year, Model & Trim Level
2005 Explorer
So, rough idle and exhaust smell have been addressed here on the forum dozens of times, but I can't seem to get a good solution.
I just have my timing chains and tensioners replaced on my 2005 4.0 Explorer. The engine now runs very rough at idle and the exhaust smells of gas. The shop that did the chain hasn't been able to figure it out.
Does anyone have any ideas?
There are no codes and it runs reasonably well when it's above 1000 RPM.
I tend to think the shop did a good job on the chain install, but I think it's likely that a electrical connector or vacuum hose is disconnected or something else that might come loose or break on removal or install.
Thanks
 



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if it runs well over 1,000 rpm and poorly at idle this might suggest a vacuum leak. As with higher RPM the engine is able to over come the leak and pull proper vacuum on the manifold but with low rpm too much bypasses the MAF and excess air is getting causing the motor to run lean..

Ask if the engine is idling lean and try unplugging the MAF to see if it smooths out. A bad MAF can also cause an engine to idle poorly but by unplugging the MAF the ECU will be forced to rely on MAP and O2 sensors.
 






Vacuum leaks sounds pretty likely. I'll try to spray around the engine and listen.
On a hunch, I unplugged and re-plugged the temp sensor, which seemed to improve the idle.
I'll keep looking and let everyone know. I'm still open to suggestions.
 






Re-seating the temp sensor plug stopped the gas smell, but not the rough idle. And I now have a #2 misfire code.
It's going back to the shop next week. I couldn't find any obvious vacuum leaks.
 






Re-seating the temp sensor plug stopped the gas smell, but not the rough idle. And I now have a #2 misfire code.
It's going back to the shop next week. I couldn't find any obvious vacuum leaks.
What was the outcome?? Can't find it anywhere on the internet.. I changed the timing components myself and checked the black links lined up at least 5 times. Put it all together and runs terrible, smells like gas, 60%+ trim on bank 1, -20%+ trim on bank 2. I can't find any vacuum leaks either. My engine is the 4.6L. When I crank over the engine it sounds terrible too, not smooth like it used to.
 






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