Last post on Dec 22, 2011 at 7:51 PM
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Isuzu, Isuzu Rodeo Sport, Auto Repair, SUV
#1 of 10 1991 rodeo high idle issues
Oct 29, 2006 (9:32 am)
Hello everyone I have a 1991 Rodeo 3.1 with an
idle issue. it is at 185,000 miles and has
slowley developed an idle issue.
115,000 miles it recieved a jasper engine.
135 the idle problem started.
it likes 2500 rpm and two things will change its
mind (for a minute anyways untill the light
changes) 1: flashing the ignition switch works
half the time and 2: coasting in gear untill the
point where speed matches gear and the tranny is
neither pushing or pulling and then the engine
will chug and i can press the clutch in and idle
i have replaced a slew of parts
including plugs cap and wires, many vaccume
hoses, MAP sensor, IAC (idle air), TPS, and
carburator gasket (its really a TBI unit)...its
time for either an EGR ($65) or fuel injectors
($105 each) does anyone have any ideas? How can
i test the injectors? Test EGR? I would really
appreciate some help this is killing gas mileage
#2 of 10 1990 cougar 3.8 high idle
Nov 06, 2006 (9:04 pm)
I recently acquired a 3.8 cougar 1990,and can not figure what is causing a high idle.The vacuum lines appear okay and disconnecting the ais motor changes nothing.Any help would be appreciated.
#3 of 10 Re: 1990 cougar 3.8 high idle [hdion75]
Dec 16, 2006 (12:00 pm)
Has anyone figured this out yet?
I have a 91 Isuzu Trooper, 2.8 TBI.
It takes about 10 tries to get the truck to start. I have to keep my foot to the floor or it won't start. It runs real rich until I get the revs up to 3-4K rpm. Then it clears up.
It does this every time I try to start it, warm or cold.
Once it starts, then it idles at around 2K rpm.
If I block the air feed to the IAS, I can get the idle down to around 850 rpm. I replaced the IAS, but there was no change. TPS is correctly set also.
The high idle sounds like a vacuum leak, but I have yet to find it. Don't know if the hard starting is related, but I assume it is.
#4 of 10 Re: 1990 cougar 3.8 high idle [hdion75]
Jan 13, 2007 (10:42 am)
Hi. Have you figured this out. I have the exact problem with my '92 Cougar. It seemed somewhat high since I've had it (about 3 months), but now it idles at 2500 in Park, about 1200 in drive with brake on. Cannot find any vac leak, but voltage is really high to the injectors. Put in an identical junkyard brain box, no change. (Of course it could also be bad . . .). Please let me know if you've made progress or had success in fixing. Thx.
#5 of 10 Re: 1991 rodeo high idle issues [loganc]
Apr 26, 2007 (2:53 pm)
My 92 ran so bad and after a while would barely start. I discovered that it was tied to the throttle body fuel injection. Drove me nuts, but found that if I pulled the ecm fuse, then started the engine, shut it down, put the fuse back, then did a reset sequence (depress accelerator slightly, start engine, run for three seconds, shut off for ten seconds, then restart) it went back to normal and has run fine for months.
#6 of 10 Re: 1991 rodeo high idle issues [mbents]
Mar 25, 2008 (8:02 pm)
It works............ I have a 93 rodeo and the ecm fuse trick works.
My Rodeo would rev to 2500 rpm when the clutch was pressed, sounded like John Force staging at the Gator nationals !
#7 of 10 Re: 1991 rodeo high idle issues [mbents]
Mar 29, 2008 (11:29 am)
Thanks very much for this answer. I just tried it on my '94 Rodeo, and it worked like a charm. After weeks of tracking vacuum hoses and checking connections without finding any solution, it's finally now not zooming up to 3,000 RPM every time it idles.
The only slight difference is that when I tried to start it without the ECM fuse in place, it wouldn't. So, I just cranked it a few seconds and stopped. Then put the fuse back in place and followed the rest of the directions. Bingo! Test drive proved no more problem.
#8 of 10 rodeo idling high
Dec 09, 2008 (6:05 pm)
hi there im new here - so bare with me i have a 1991 4 cylinder 2.6 rodeo and i have been in here reading up on the high idling issues ... mine is idlying at around 1200-1500rpm and cant seem to find where to knock the idling speed down, there is one by the throttle cable/arm adjusted that --made no difference -- any ideas would be greatly appreciated
Cheers Kev - ozziwi
#9 of 10 High Idling solved
Nov 29, 2010 (6:42 pm)
Rodeo 98 2.2L 5 speed
Got mine used about 2 months ago with 222,000 miles from a car auction but it was very well maintain for what I can see, but after a week start idling to around 1500 to 2000 rpm. Went to Auto Zone and got a product called " Sea Foam " and added to my full tank of gas and after a week is idling at 750 rpm that should be normal idling speed . And by the way there is no idling adjustments on the ones w/throttle body. Good Luck. Hope this help in some way.
Dec 22, 2011 (7:51 pm)
I have a 92 rodeo with an idle problem it idles high at times then normal. constistantly goes back and forth, I want to try thr ecm fuse but am not sure where it is. Can someone please tell me where this fuse is?