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Losing power around 3000-3500 RPMs

Whodat

New Member
Joined
Jul 31, 2020
Messages
4
Location
Sandy Hook, CT
2003 TJ 4.0: Having a [email protected]# of a time diagnosing the problem. So far I've replaced the TPS (not Mopar), all Injectors, all Plugs (correctly gapped), Fuel Pump and Rear Fuel Lines. Cats seem to be working as I'm getting temps roughly 100-150º higher downstream. Starts great, Idles good but it has no power....almost zero up slight hills. Any ideas on what it could be?

Thanks.
 
Last edited:

TJ Jim

TJ Enthusiast
Joined
Feb 12, 2021
Messages
576
Location
Tennessee
What are you doing when you are hitting 3500 rpm? If I push my Jeep to that rpm through the gears I am hauling ass. Like I’m getting on the interstate ahead of a flying 18 wheeler.
 

JKP

TJ Enthusiast
Joined
Aug 20, 2020
Messages
676
Location
Warner Robins GA
Your cats are most likely plugged. Take out the upper O2 sensors and see if it runs better. Or drop the precats from the manifold and look inside.
 
OP
Whodat

Whodat

New Member
Joined
Jul 31, 2020
Messages
4
Location
Sandy Hook, CT
What are you doing when you are hitting 3500 rpm? If I push my Jeep to that rpm through the gears I am hauling ass. Like I’m getting on the interstate ahead of a flying 18 wheele
Ha. I'm usually in the next gear as well. What I'm saying is the engine won't even rev.
 

TJ Jim

TJ Enthusiast
Joined
Feb 12, 2021
Messages
576
Location
Tennessee
If you are height/arm length challenged or old and stiff you will find it easier to pull the drivers side fender off to gain access to the exhaust bolts. There are probably thirteen bolts and two or three electrical connections to remove and it'll add maybe an hour to the job.
 
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