Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Jamie on March 31, 2008, 06:34:55 PM

Title: Wrangler running problem
Post by: Jamie on March 31, 2008, 06:34:55 PM
Hi everyone! I've had a fault with my 1999 V reg Wrangler 4.0L sport for over 18 months now, and despite several visits to local garages, no-one has (yet) solved it... I wonder if someone could please help! Every time I run it, as it approaches normal operating temp, it starts spluttering, back firing and if stuck at traffic lights or similar, the revs will go all over the place. It has had a new 'mapping sensor' as one garage thought it was that, but no change at all! It's really annoying as its a nightmare to drive now. After 10 mins or so, it seems to clear itself and drives ok (if a bit under powered). Has any body experienced a similar fault? P.S It seems to spit out a fair bit of moisture from exhaust system - may this be linked or normal? Thanks in advance, Jamie down in N.Devon
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Post by: Mike Pavelin on March 31, 2008, 06:53:02 PM
It sounds like the upstream oxygen sensor.
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Post by: german guy on March 31, 2008, 08:44:15 PM
or coolant temp sensor
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Post by: Manda on March 31, 2008, 10:29:12 PM
Hi Jamie, mine ('97 Wrangler) did that on and off for ages. We eventually pinned it down to the oxygen upstream sensor. The sensor was loose  :roll:
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Post by: bonza on April 01, 2008, 03:08:12 AM
yes. sounds like the upstream sensor is causing this problem.

the sensor is ignored when the engine is cold, then comes into affect when up to normal running temperature.