Very erratic idle on JGC 1997 5.2 liter engine ?
 

With engine warm, and in neutral, the engine goes rapidly up and down from
about 200 rpm (almost shuts off) to 500 rpm. It just rapidly
oscillates back and forth between 200-500 rpm.


On cold crankup, engine shoots up to about 2200 rpm, much too high rpm for a
cold engine.

Other than erratic idle speed and fast rpm on cold starts, the engine runs
great and is strong.

What are the most likely culprits, please ?

I will appreciate any help on this.

Thanks !!

--James--

Re: Very erratic idle on JGC 1997 5.2 liter engine ?
 

James Nipper did pass the time by typing:
> With engine warm, and in neutral, the engine goes rapidly up and down from
> about 200 rpm (almost shuts off) to 500 rpm. It just rapidly
> oscillates back and forth between 200-500 rpm.
>
>
> On cold crankup, engine shoots up to about 2200 rpm, much too high rpm for a
> cold engine.
>
> Other than erratic idle speed and fast rpm on cold starts, the engine runs
> great and is strong.
>
> What are the most likely culprits, please ?

Starty by cleaning your throttle body idle air passage.
This is for the I6 but the concept is the same.

http://members.cox.net/wilsond/tb/tb.html

--
DougW

Re: Very erratic idle on JGC 1997 5.2 liter engine ?
 

James Nipper did pass the time by typing:
> With engine warm, and in neutral, the engine goes rapidly up and down from
> about 200 rpm (almost shuts off) to 500 rpm. It just rapidly
> oscillates back and forth between 200-500 rpm.
>
>
> On cold crankup, engine shoots up to about 2200 rpm, much too high rpm for a
> cold engine.
>
> Other than erratic idle speed and fast rpm on cold starts, the engine runs
> great and is strong.
>
> What are the most likely culprits, please ?

Starty by cleaning your throttle body idle air passage.
This is for the I6 but the concept is the same.

http://members.cox.net/wilsond/tb/tb.html

--
DougW

Re: Very erratic idle on JGC 1997 5.2 liter engine ?
 

James Nipper did pass the time by typing:
> With engine warm, and in neutral, the engine goes rapidly up and down from
> about 200 rpm (almost shuts off) to 500 rpm. It just rapidly
> oscillates back and forth between 200-500 rpm.
>
>
> On cold crankup, engine shoots up to about 2200 rpm, much too high rpm for a
> cold engine.
>
> Other than erratic idle speed and fast rpm on cold starts, the engine runs
> great and is strong.
>
> What are the most likely culprits, please ?

Starty by cleaning your throttle body idle air passage.
This is for the I6 but the concept is the same.

http://members.cox.net/wilsond/tb/tb.html

--
DougW