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2005 Ford F-150 Repair Question


Topics covered: Engine, Rpm, Sensor.
Mileage: 100,000 miles.

Asked on August 8, 2012

Everytime i turn my a/c on my truck the rpm goes up and down is it the throttle position sensor?

The rpm goes up and down like it wants to die

Answer

Replied on 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

Tiny Answered by ASEMaster6371 (expert)
24,854 answers provided
Replied on August 8, 2012

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

Tiny Response from Abel Talamantes
1 question asked
Replied on August 8, 2012

yes, along the intake manifold. you may need some help if you are not familiar with this operation

Roy

Tiny Answered by ASEMaster6371 (expert)
24,854 answers provided

Replied on August 8, 2012

What would replacing the throttle position do?

Tiny Response from Abel Talamantes
1 question asked
Replied on August 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.

Tiny Answered by mhpautos (expert)
26,916 answers provided
Replied on August 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 Answered by salvadormendoza
0 questions asked

Replied on August 17, 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.

Tiny Answered by M_H_RITZEL (expert)
2,685 answers provided
Replied on August 18, 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 Response from Abel Talamantes
1 question asked