Erratic idle
Thread Starter
|
4th Gear
Joined: Oct 2023
Posts: 4
Likes: 2
Erratic idle
So I have a 2002 ford f150 4.6 4x4. This problem has been going on for years. The truck will literally just be idling fine then just start revving up out of nowhere. Sometimes when I crank it it’ll rev super high and just hold there, I can cut it back off and restart and it’ll start normal and drop to idle. When the AC is on when the compressor cycles sometimes it’ll rev real high. There’s no roughness no loss of power or any codes whatsoever. Any thoughts or help is greatly appreciated. I’m at a loss here, thanks in advance.
Fleet Mechanic
Joined: Jun 2023
Posts: 1,394
Likes: 384
From: WA
Could be the IAC valve. But since the problem is intermittent it will be hard to diagnose. Might be worthwhile to pop it off and see how it looks inside. Supposedly you're not supposed to clean them but people do, with no problems. Check the electrical connections too.
Not suggesting you buy and swap but it looks like this.
https://www.rockauto.com/en/catalog/...ac)+valve,6072
Not suggesting you buy and swap but it looks like this.
https://www.rockauto.com/en/catalog/...ac)+valve,6072
Fleet Mechanic
Joined: Jun 2023
Posts: 1,394
Likes: 384
From: WA
If the idle goes high and you have time get out and unplug the IACV. If the idle RPM drops, and/or the engine dies at least you'll be closer to the cause.
Engine RPM is controlled by air flow. Your throttle body is mechanical, so unless you have a piece of carpet or a big boot accidentally on the throttle pedal, the IACV is the place to look. Could be physically sticking or it could be the electrical control signals.
Engine RPM is controlled by air flow. Your throttle body is mechanical, so unless you have a piece of carpet or a big boot accidentally on the throttle pedal, the IACV is the place to look. Could be physically sticking or it could be the electrical control signals.
Thread
Thread Starter
Forum
Replies
Last Post
ebbnflow
1999 - 2003 7.3L Power Stroke Diesel
2
May 31, 2013 03:08 PM
stangbanger
1987 - 1996 F150 & Larger F-Series Trucks
11
Nov 25, 2008 12:37 AM
