Every time I turn my A/C on my truck the RPM goes up and down

RASMATAZ

MECHANIC
75,992 POSTS

Lean fuel condition could be caused by one of the following below:

1. Vacuum leaks
2. EGR and PCV valve.
3. Low fuel pressure.
4. Dirty fuel injectors.
5. Mass Air Flow Sensor.
6. Oxygen Sensor.

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Monday, June 8th, 2020 AT 5:08 PM (Merged)

EMILYEMERY

MEMBER
3 POSTS

Thanks I'll try some of these.

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Monday, June 8th, 2020 AT 5:08 PM (Merged)

CATHYHUNTER

MEMBER
8 POSTS
2001 FORD F-150

Engine Performance problem
2001 Ford F150 V8 Four Wheel Drive Automatic

first thanks to all the help so far.
After replacing battery fires up great and runs well throughout day. Morning idle is low does not want to stay running. Takes about 5 minutes to reach proper idle. Had weatherized next morning started fine but today same idle problem.

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Monday, June 8th, 2020 AT 5:09 PM (Merged)

BLACKOP555

MECHANIC
10,371 POSTS

Sounds like another tech is helping you? Hit reply to question at the bottom of the page of your original topic that way you keep all the information there and the tech that was helping you will be able to continue doing so.

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Monday, June 8th, 2020 AT 5:09 PM (Merged)

FIRELT4

MEMBER
1 POST
2001 FORD F-150
V8
4WD
AUTOMATIC
125,000 MILES

My 2001f150 5.4 idles rough upon startup and the rpms will jump from 1000 to about 1300 to 1500 and crash to 0 causing the truck to go dead it doesnt go dead all the time only in spurts

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Monday, June 8th, 2020 AT 5:09 PM (Merged)

RASMATAZ

MECHANIC
75,992 POSTS

Hi firelt4, Welcome to 2carpros and TY for the donation

Clean out the idle air control valve and test throttle position and mass airflow sensors

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Monday, June 8th, 2020 AT 5:09 PM (Merged)

MISSCARA

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1 POST
2001 FORD F-150
V8
4WD
AUTOMATIC
200,000 MILES

Why does my 2000 ford f 150 idle hard up and down in park

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Monday, June 8th, 2020 AT 5:09 PM (Merged)

MIKE H R

MECHANIC
3,094 POSTS

Could be a number of reasons, Has the truck had a tune up? Is there any error codes? Even some times a small piece of carbon can get into the throttle body and partially clog a air hole. As I say there could be one of a number of things.

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Monday, June 8th, 2020 AT 5:09 PM (Merged)

JHETUE

MEMBER
2 POSTS
2001 FORD F-150
5.4L
V8
4WD
AUTOMATIC
230,000 MILES

At low rpm's idle surges drastically. I replaced intake, IAC, DPFE, TPS, COP, plugs. All of the vacuum lines. The EGR, and MAF. Could the 02 sensors and catalytic converters cause such a surging idle?

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Monday, June 8th, 2020 AT 5:09 PM (Merged)

JHETUE

MEMBER
2 POSTS

Also, I replaced all fuel injectors.

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Monday, June 8th, 2020 AT 5:09 PM (Merged)

HMAC300

MECHANIC
48,601 POSTS

Clean throttle plate and IAC hole on both sides with choke cleaner. Then look for an air leak like valve cover grommets, and vacuum lines.

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Monday, June 8th, 2020 AT 5:09 PM (Merged)

HMAC300

MECHANIC
48,601 POSTS

Also scan for codes and check fuel pressure with a gauge auto parts rent it. See link.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator