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Discussion Starter · #1 ·
My 07FJC 4WD 58k miles has developed a strange and very annoying surge when the engine is lugged between 2000 and 3000 RPM. When you are accelerating very slowly or at full speed, the engine runs fine. However, when you are accelerating moderately, but not enough to cause a downshift the engine will hesitate two or three times when going through this part of the power band. I have brought it to the dealer twice and they have tried cleaning the fuel injection and syncing the throttle bodies to no avail. They say there are no engine codes. I can't tolerate this anymore. Any suggestions?
 

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I assume you have a 5AT?

Have you cleaned your MAF and made sure your air filter was clean? Your due for spark plugs in 2K so it wouldn't be a bad idea to change those out at the same time.

DEWFPO
 

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Discussion Starter · #4 ·
wheels and tires stock. no mods whatsoever. cleaned MAF, air filter new...I will change at 60k but dealer said they were ok. Any other suggestions?
 

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Just some thoughts.....I've re-read your post and typically mid-throttle surging or hesitating as you described is caused by ECM not being able to adjust the air fuel ratio properly. A vacuum leak, a leak in the air intake system after the MAF, bad MAF, bad throttle position sensor, exhaust leak, bad O2 sensor.......something like that. Some of these sensors can be out of spec. but not so bad that they set a code yet.

DEWFPO
 

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Discussion Starter · #6 ·
I tend to agree but my dealer didn't find anything.They said they checked the ECM and spark plugs, cleaned the fuel injection system and readjusted the throttle bodies. My dealer is piss poor at troubleshooting so I am not really suprised. They usually give it a few hours of effort and then give up and tell me that they don't know how to fix it and send me home with no satisfaction. Any suggestion as to how to troubleshoot this issue?
 

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I accidentally overfilled my rear dif and it caused a weird shifting sensation. Once I drained it back to normal level it ran smooth again.

Just a thought.
 

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Any suggestion as to how to troubleshoot this issue?
I'm not an ASE certified Toyota tech by any shape of the imagination, but it seems to me they can attach their high dollar OBDII diagnostic tool and have it record real time sensor data and log it while you drive the vehicle and cause it to misbehave. They can then look at the sensor values and see it they are all in proper operating ranges. It's probably something subtle that's not so bad that it's setting a code but a good diagnostic tech should be able to look at the actual sensor values and make a determination.

DEWFPO
 

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Start with the small chep stuff first. MAF sensor, air filter, and plugs. I doubt your dealer would "check" your plugs.:cheers:

I have had weird issues in a 4runner when it's plugs were shot. As soon as I replaced them she was as good as new.
 

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Discussion Starter · #10 ·
So after a second trip to the dealer, the finally fixed the problem. Turns out it was a bad fuel pump. Got it back and it runs like a champ. Kudos to Price Leblanc Toyota in Baton Rouge for sticking with it and fixing the problem.
 

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I have exactly this problem and toyota even replaced the tranny even though i thought it was a fuel problem. Since then they cleaned the throttle body and claimed they dont notice it.
Could it still be the fuel pump even though a fuel return test was good?
 

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So after a second trip to the dealer, the finally fixed the problem. Turns out it was a bad fuel pump. Got it back and it runs like a champ. Kudos to Price Leblanc Toyota in Baton Rouge for sticking with it and fixing the problem.
Glad you got it fixed. If they had looked at the Long Term Fuel Trim the first time they worked on it they would have seen Positive double digit numbers as the PCM was trying to correct a lean condition from the restricted fuel flow from the tank.
 

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I am on the brink of trading this thing in if i cant figure out the surging/hesitation problem. Is it possible the fuel pump is bad even though there are no codes and fuel return test was good?
 

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Jimmie will be your Huckleberry to answer that specifically.

I'd imagine not, but I've noticed the following phenomena, in regards to CEL. I continually threw a MAF code over the course of a couple of weeks, and I disregarded due to lack of time. I never "recalibrated the ECU" (how'd you like that verbiage that Firestone gave another member here, jimiee?. Hahahaha) BUT the code had mysteriously ceased, though I knew that the MAF needed cleaned.

For what it's worth.
 

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I have had this surging problem for 35k miles now and have yet to have any codes show up. accelerating up hill sucks.
 

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I know this is an old post, but has anyone else been able to fix this issue? I have replaced the MAF sensor, cleaned the throttle body, replaced the plugs, reset the ECU, etc. to no avail.
 

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I thought replacing the fuel pump fixed it but the problem quickly came back. I have settled on masking the problem by using 89 and 93 octane and I also installed the sprint booster. I am happy now other than the bad gas mileage.


Sent from AutoGuide.com Free App
 

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Ok I just wanted to post on this topic because I think I have a fix for it, I have had the same issue for about 20K or more ( no codes ) and it was very lite surge but has slowly gotten worse. it only surges while under a medium throttle , slow throttle not problem and full peddle to the floor no problem.

I have a 2007 Fj with auto trans now with right at 100K miles on it. but the problem started around 70k miles, and has gotten more noticeable. So for a while now I would add injector cleaner about every 10K ( sea foam , etc ) and it would at first help and mask the problem or temporary fix the issue. but always came back. And I always kept up on the oil changes , and air filter , etc and at about 70K when this first started I even changed the spark plugs with 100k spark plugs . every thing I did helped but never fixed the surge problem. Now I am at 100k and I have never cleaned the MAF sensor, so I went and got some contact cleaner and cleaned it, once again it helped ( I am sure it needed it ) but it was not what was causing the surge. So I have searched and not to many people have post of this issue, I did find on another Toyota car forum the same complaint and the fix was to replace the A/F sensor, so At 80 $ plus dollar a sensor I figured at 100k if its not the problem it would be about time to replace anyways so I just replaced both A/F sensor and it seems to have fixed it, I say that because its only been a few days but no surge. And it kind of makes sense because At first you can not feel the surge when the engine is cold but as soon as you drive it a few miles and it warms up it would come back. As when the sensors are cold you are running rich and then it leans it out . long story short try A/F sensors I have seen them for as much as 145$ but found some on Ebay for 80 ish. I will also say they are a real pain to reach !
 

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Ha! And I just bought a CAI to mask the problem even more! I will look into this. Thanks!


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