Jeep revs itself at startup and intermittently - also, code P-1494. - JeepForum.com
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Go Back JeepForum.com > Models > Jeep Wrangler Forums > TJ Wrangler Technical Forum > Jeep revs itself at startup and intermittently - also, code P-1494.

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Unread 07-03-2010, 03:58 PM   #1
TheMightyGoat
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2003 TJ Wrangler 
 
Join Date: Jul 2007
Location: Vermont
Posts: 330
Jeep revs itself at startup and intermittently - also, code P-1494.

As of about a week ago, every time I start my Jeep it revs itself up to about 2k RPM before settling back in around 750. If I just sit at idle, it'll stay there for a while and then climb back up to about 2k again. It went almost up to 3k once. Then it alternates back and forth.

If I drive, it does the same thing; I was cruising by a shopping plaza a few days ago, so I was just coasting in second without touching the gas, as there were a lot of pedestrians around, and all on its own the Jeep revs up and exceeds 15mph when I had been going about 5mph through the foot traffic. I don't notice it once I'm beyond second gear, 'cause stepping on the gas doesn't do anything above second gear anyway.

Notes:
1) The only code on there has been on there for about 2 years, and I never bothered to fix it. P-1494. Leak detection pump? Don't think that's related.
2) About two weeks ago, about a week before the Jeep started throttling itself, I noticed that the clutch pedal started to click when I depress it - but only sometimes. Probably unrelated. I did have the clutch replaced recently though.
3) It's not as though the cable is sticking. The Jeep revs itself without me touching the gas pedal, and it'll alternate back and forth without me touching the pedal.
4) Maybe I need to clean out the throttle body? Sensor telling the computer the engine isn't getting enough oxygen?

#4 is my best thought and if cleaning out the throttle body doesn't make any difference I s'pose I'll try to track down that code. Anyone have any better ideas?

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Unread 07-03-2010, 04:14 PM   #2
SnoqulmieTJ
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1999 TJ Wrangler 
 
Join Date: Jan 2009
Location: NorthBend, Washington
Posts: 180
my jeep did that for a while then the rpm started to become eratic opon start up so i research this forum and found the the o2 sensor my be bad so i unplugged the one on hte manafold and so far so good. no rpm problems better milage, so i guess i need to replace the o2 sensor. I dont now if this is your same prob but it doesnt hurt to try and narrow down this real problem before taking it to the rip off artists.
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Unread 07-03-2010, 04:17 PM   #3
TheMightyGoat
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2003 TJ Wrangler 
 
Join Date: Jul 2007
Location: Vermont
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Quote:
Originally Posted by SnoqulmieTJ View Post
my jeep did that for a while then the rpm started to become eratic opon start up so i research this forum and found the the o2 sensor my be bad so i unplugged the one on hte manafold and so far so good. no rpm problems better milage, so i guess i need to replace the o2 sensor. I dont now if this is your same prob but it doesnt hurt to try and narrow down this real problem before taking it to the rip off artists.
No code on yours?

I just looked around the leak detection pump... had a vacuum line unhooked. Probably been like that for a couple years. Hooked it back up. Made no difference on the RPMs, but I bet that's what the code was about.

The oxygen sensor seems plausible. I'll see if I can change that next week when I'm on vacation. Any more input?
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Unread 07-03-2010, 04:20 PM   #4
SnoqulmieTJ
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1999 TJ Wrangler 
 
Join Date: Jan 2009
Location: NorthBend, Washington
Posts: 180
Just unplugg it at first to see if there is a change, the factory settings are pritty good so you should se a change if the o2 sensor is bad. if not then try the other one after the cat to see if that on is bad. i know there is about 10 things that can lead to these same symptoms so it is a chore to figure it out i have been dealing with this same thing for about a month now and i think i have it figured out
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Unread 07-10-2010, 08:16 PM   #5
TheMightyGoat
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Well I've gone through all the oxygen sensors in the exhaust, with no change. I think tomorrow I'll try cleaning out the throttle body... even though I did that a little over a year ago.
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