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Discussion Starter #1
Hi FJ world
I joined a few weeks ago and am impressed with the site. I have a 2007 FJ, a 2007HHR, and a 1975 Scout. My quest right now is a problem with the FJ. It hunts or surges when releasing the gas pedal while stopping- it has a manual transmission. The motor revs up to 2300 rpm and down to 1000, then back up again one or two more times, then levels out around 1000. It may drop to about 500rpm and run rough. The check engine light is on as well as the trac lights. I changed plugs but no change in the issue. Any ideas?
 

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Hi FJ world
I joined a few weeks ago and am impressed with the site. I have a 2007 FJ, a 2007HHR, and a 1975 Scout. My quest right now is a problem with the FJ. It hunts or surges when releasing the gas pedal while stopping- it has a manual transmission. The motor revs up to 2300 rpm and down to 1000, then back up again one or two more times, then levels out around 1000. It may drop to about 500rpm and run rough. The check engine light is on as well as the trac lights. I changed plugs but no change in the issue. Any ideas?
Obviously, the FIRST thing to do is to determine what OBD-II fault codes triggered the Check Engine Light.

That will then lead you down a rational, informed troubleshooting path, rather than blind, expensive, random parts-replacement strategy.
 

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Discussion Starter #3
Thanks for the reminder FJtest. On My recent elk hunt in the East Kootenays the check engine light came on. The codes included P0171 and P0174. I have read the possible causes these report. In addition the motor is hunting> It goes from 2300RPM to 500 and usually settles around1000 or sometimes stays at 1500. There is also a miss-the code reader mentioned this as well. The lights came on for traction control, SS, VSC OFF, VSC TRAC. Any thoughts? There does not seem to be much info that I have found> Thanks for any ideas, Dave.
 

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Did you search "P0171" on this forum? There is a ton of troubleshooting info archived here.

In a nutshell. P0171 indicates that the engine ECU "thinks" cylinder bank #1 (passenger side) is running lean, and P0174 indicates that the engine ECU thinks cylinder bank #2 is running lean.

You don't know yet if there is actually a lean condition, or if the ECU is getting bad data from the various sensors that control fuel/air ratio. The surging, hunting, and (reported) lean mixture are frequently signs of an air leak into the intake system.

So, search the forum for "P0171" for tech details and tales of other people's experiences, and:
1. How many miles are on your odometer?
2. When was the last time the MAF sensor was cleaned?
3. When was the last time the air-fuel and oxygen sensors were replaced?
4. Have you checked for any air leaks into the intake tract on the engine side of the throttle body? Loose intake manifold bolts? Loose throttle body bolts? Disconnected PCV valve hose?
5. If more than 150K miles, has the fuel pump ever been replaced?
6. Etc, etc.
 

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fjtest gave good advice, I have nothing else to offer. but back in the early 80's I had a 76 Scout,ragtop. unfortunately suffered from rust. I was out playing Rat Patrol and blew out the sides. Addded a roll bar to hold it together.
 

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Discussion Starter #6
I thank you both for your assistance. Starting tonight I will be getting my nose out of the manuals and getting my hands dirty. The FJ has 89,719 miles.
 

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Welcome
 

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Discussion Starter #8
To the members who helped with ideas about my problem. The issue was due to the ventilation hose falling off the tube on the cover over the motor. I was about to dive in to the guts of the beast when I decided to check the fuses. As I did, I looked at a hose I had checked at the beginning when the FJ started acting up. It seemed to go nowhere and being an old guy figured it was a vent hose. At the time I did not realize that it had a place to hook onto. Over the last few weeks I've learned a lot. I looked closer and found a nozzle coming from the cover with a hole in it. The hose fit right on! The truck is running fine again, Thanks to all!!
 

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Welcome from Oregon :)

Good catch!
 

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Welcome aboard!
 
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