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LS1 MISFIRE, Misfire goes away when intake air sensor (IAT) is disconnected?

RSS570

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VX SS 2001 5.7 LS1 4L65E
Hi guys,

I have a VX SS, LS1, mafless, otr, cam, exhaust, the problem is the car seems to bog down at low rpm when accelerating (sometimes even die untill I back off) and surge while driving at low rpm, feels like a misfire?

When I disconnect the intake air temp sensor (IAT) after the motor has warmed the misfire goes away and the car launches like a champ and has alot more horsepower?

When I start the car cold with the (IAT) sensor unplugged it bogs down when put into gear and stalls, I guess this is due to the engine being cold.
Onece the engine is warm with the (IAT) sensor unplugged I can shift into gear without the engine stalling.

I have changed the leads, plugs, o2 sensors, IAC, TPS and fuel filter to no avail.
I have checked the coils and for vacume leaks. Is there a fool proof way of checking this?

Could this issue just be a faulty IAT sensor or is this somthing someone else has come across?

Cheers
 

RSS570

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Im trying not to take it to a tuner as I do not have one or know a reliable one that will do the job for a reasonable price on the Gold Coast?

Any information would great.
 

07GTS

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VEGTS BUILT BLOWN E85
with a mafless tune the iat is one of the sensors is use to calculate how much air is going into the engine, if u unplug it it will default to -40 deg and will pump more fuel in, so if that helps id say get your tuner to have a look and check the af ratio at those low rpm high load area, also the tuner can see if any of the sensors are playing up either..
 

RSS570

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Does anyone know of a quality tuner on the gold coast they have used or know someone that has. Thanks
 

RSS570

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Issue resolved. The fuel line between the fuel pump and the top of the pump assembly had failed causing low fuel pressure.
Car starts and runs perfectly onece rectified. If you are having missfire issues fuel pressure is one of the first thing worth checking.

Also found that the ebay non genuine tps was poor quality and had pulled apart internaly. Recommend buying genuine only.

Thanks.
 
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