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VU flat spot?

Mad84VK

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Hey guys, so my girlfriend bought a V6 VU which is pretty clean.
The only problem is that at random there will be a flat spot where there is no power then all of a sudden it kicks in and you get a massive amount of power.
It doesn't idle rough or anything, and the flat spot only happens in between idle and flat stick.
I have had lots of people say different things like, O2 sensor, Tune, injectors, intake sensor, etc
But i was just wondering if anyone had more of an idea.
Thanks
 

MR_VX

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Maybe the throttle body needs a clean, it maybe caked up with carbon and sticking. Or check the plugs and clean the air flow sensor to.
 

SavVYute

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Might be worth checking your throttle position sensor is working properly. They're a moving part and prone to wear or play up.


A throttle position sensor works as a potentiometer, sending variable voltage signals to a car's main computer to let it know how far the throttle plates have opened. The engine then uses this data to calculate the proper mix of air to fuel the car's needs at that moment for optimal performance. The sensor feeds a low-level signal--typically less than one volt--to indicate a fully closed throttle, adding voltage gradually as the throttle opens and sending a full five volts when the throttle opens completely.

A car that seems to hesitate or stumble during acceleration may have a faulty throttle position sensor. If the sensor sends the wrong throttle position message to the engine, the engine will not add extra fuel to the mixture until the oxygen sensor feedback circuit steps in to correct the imbalance. This momentary miscommunication will cause the car to hesitate. Sometimes a sensor may develop one or more dead spots in its response, so as the potentiometer passes those spots, the car hesitates. Sensor wear often causes a dead spot just above its normal "idling" position.
 

franklinfrog

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^^^^ Can't argue with that, he must write encyclopaedias in his spare time. They're pretty cheap and easy to replace if you don't have a multimeter to test voltage output.
 

Mad84VK

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thanks heaps man ! i will have a look, im going away for a week but when i get back i will be sure to start there and let you know what happens.

is there any cleaning agents i can try first before i buy a new one or do i just use a multi-meter ? If so how do i know how it is screwed?
 

SavVYute

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I think your VU tps is a sealed unit, so cleaning contacts wouldn't be an option.
Should throw a code if it is faulty.
 

VX Exec

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I've got the same problem here, its most prominent in fourth (which seems to have no power at all).Im looking at changing the plugs, new coil-pack and clean the plenum and whatnot to see if it goes away, let us know what happens mate!
 

Mad84VK

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Have changed plugs, leads and cleaned the throttle body.
I'm guessing its a sensor so i will start on them next.
I'm going to reset the computer so i can see what new error codes come up.
Work it out form there!
 

Mad84VK

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Off to holden next week to work it out!
 

markbaja

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Did you change the throttle position sensor as suggested?

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