Irregular idle '89 Pioneer

I have an '89 4.0 Cherokee Pioneer. I have been having an idle problem for
some time. Sometimes, first thing in the morning, or after work on my way
home, when I start it, it will idle way up at 2500 rpm for a while until I
shut it down and try again. Sometimes (usually in the summer) parked in the
hot sun but a cold engine, it will start fine, but when I go the idle will
be so low it will stall, this is very annoying, it will be stalling one
minute and the next minute it I am idling about 1800 rpm, coming to a stop
sign I have to really press hard on the brake (or throw it in neutral) and
sit there like a moron with my engine revved up.

I have taken it twice to my works mechanics (commercial) over the past years
and they did something to it that worked fine for a year then the problem
came back. I have a new vacuum hose harness. (but some hoses are old)

Richard

Our 88 does that every couple years and every couple years I open the
electrical plug on the TPS (throttle position sensor) on the throttle
body and clean the contacts inside. That does the trick for us. I use
a real spray contact cleaner usually, but WD40 will do in a pinch.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Richard wrote:
>
> I have an '89 4.0 Cherokee Pioneer. I have been having an idle problem for
> some time. Sometimes, first thing in the morning, or after work on my way
> home, when I start it, it will idle way up at 2500 rpm for a while until I
> shut it down and try again. Sometimes (usually in the summer) parked in the
> hot sun but a cold engine, it will start fine, but when I go the idle will
> be so low it will stall, this is very annoying, it will be stalling one
> minute and the next minute it I am idling about 1800 rpm, coming to a stop
> sign I have to really press hard on the brake (or throw it in neutral) and
> sit there like a moron with my engine revved up.
>
> I have taken it twice to my works mechanics (commercial) over the past years
> and they did something to it that worked fine for a year then the problem
> came back. I have a new vacuum hose harness. (but some hoses are old)
>
> Richard

That must have been it because I merely unclipped it and blew off some dust
and it runs like a champ! I bought some cleaner, I will do it right
tomorrow. Thanks!


"Mike Romain" > wrote in message
...
> Our 88 does that every couple years and every couple years I open the
> electrical plug on the TPS (throttle position sensor) on the throttle
> body and clean the contacts inside. That does the trick for us. I use
> a real spray contact cleaner usually, but WD40 will do in a pinch.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Richard wrote:
> >
> > I have an '89 4.0 Cherokee Pioneer. I have been having an idle problem
for
> > some time. Sometimes, first thing in the morning, or after work on my
way
> > home, when I start it, it will idle way up at 2500 rpm for a while until
I
> > shut it down and try again. Sometimes (usually in the summer) parked in
the
> > hot sun but a cold engine, it will start fine, but when I go the idle
will
> > be so low it will stall, this is very annoying, it will be stalling one
> > minute and the next minute it I am idling about 1800 rpm, coming to a
stop
> > sign I have to really press hard on the brake (or throw it in neutral)
and
> > sit there like a moron with my engine revved up.
> >
> > I have taken it twice to my works mechanics (commercial) over the past
years
> > and they did something to it that worked fine for a year then the
problem
> > came back. I have a new vacuum hose harness. (but some hoses are old)
> >
> > Richard