Mechanics

EVERYTIME I TURN MY A/C ON MY TRUCK THE RPM GOES UP AND DOWN IS IT THE THROTTLE POSITION SENSOR?

2005 Ford F-150 • 100,000 miles

The rpm goes up and down like it wants to die
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Abel Talamantes
August 8, 2012.




Most likely not. Look for any vacuum leaks first. If all ok, I would look at the iac motor. It may be bad.

Roy

Where exactly could I look for leaks sorry im not good with engines. Is it in the intake?

Tiny
Abel Talamantes
Aug 8, 2012.
Yes, along the intake manifold. You may need some help if you are not familiar with this operation

Roy
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What would replacing the throttle position do?

Tiny
Abel Talamantes
Aug 8, 2012.
First check to see if the A/C is cycling as fast as the speed variation, if it is only doing it in conjunction with the A/C on I doubt that it will be a faulty IAC.

Mhpautos
Aug 8, 2012.
This also hapen when u or I turn off my engine of 2002 f150 and turn on like hour later rpm needle goes up and down like for a 4 minutes look s like normal because I take the truck to cervise they never find enithing in my opinion this us nothing to worry about hope this help

Tiny
Salvadormendoza
Aug 8, 2012.
Sounds like the throttle body sensor, Under normal conditions when the engine is running each time the air conditioning kicks on there will be a drop in idle speed. This is caused by the extra strain on the engine. When the compressor shuts off then it should be normal. As far as the reving up, have found that the position sensor can make the truck do that.

M_H_RITZEL
Aug 17, 2012.
So it isn't the throttle position sensor than? Or could it be the vacuum that's dirty because when I trurn the ac on and the Rpm goes up and Down. Then I step on it on park or neutral the truck dies.

Tiny
Abel Talamantes
Aug 18, 2012.

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