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Unread 07-12-2010, 05:35 PM   #1
taterkins02
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1992 YJ Wrangler 
 
Join Date: Aug 2008
Location: Mercersburg
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4.0 problems

my 93 wrangler 4.0, it idles fine, you can rev the guts out of it while its sitting there, but when you go down the road and the engine gets warmer it gets a hesitation then it loses power. what could be the problem? could it be the cps? and if so is there a way you can test them?

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Unread 07-12-2010, 05:38 PM   #2
clush
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1994 YJ Wrangler 
 
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must be a common issue. mine is similar, and it has gotten worse over time.
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Unread 07-12-2010, 05:40 PM   #3
laybackman
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Quote:
Originally Posted by taterkins02 View Post
my 93 wrangler 4.0, it idles fine, you can rev the guts out of it while its sitting there, but when you go down the road and the engine gets warmer it gets a hesitation then it loses power. what could be the problem? could it be the cps? and if so is there a way you can test them?
How old is the cat converter? When they start to go bad they will begin to hurt high end peformance and then it just keeps getting worrse until it starts to literally choke an engine off when it gets hot. It gets progressively worse over time.
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Unread 07-12-2010, 05:43 PM   #4
taterkins02
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its a hollow cat. i changed out the tps and map, and still does it, so theyre not the problem.
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Unread 07-12-2010, 06:32 PM   #5
idaholtby
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1991 YJ Wrangler 
 
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Check your fuel pressure at the rail and report back.
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Unread 07-12-2010, 06:32 PM   #6
Roadyy
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When was the last time the fuel filter was changed?
Have you checked for codes?
You mite want to pick up a fuel pressure gauge and run it to the inside so you can monitor it while driving to see what the psi is when it starts acting up.
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Unread 07-12-2010, 07:09 PM   #7
idaholtby
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Quote:
Originally Posted by UABYJ94 View Post
When was the last time the fuel filter was changed?
Have you checked for codes?
You mite want to pick up a fuel pressure gauge and run it to the inside so you can monitor it while driving to see what the psi is when it starts acting up.
Like he said ^^^
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Unread 07-12-2010, 08:16 PM   #8
laybackman
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Quote:
Originally Posted by taterkins02 View Post
its a hollow cat. i changed out the tps and map, and still does it, so theyre not the problem.
When you changed the sensors did you dump the learned memory in the ECM? I would have.
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