Won't rev past 3k rpm when accerating

Cerrito

New member
I have a 98 the with 225k miles. I have a 4in lift and 35 inch tires but the problem existed well before those add ons all stock. When I accelerate onto the highway, foot on the floor, the jeep won't rev past 3k rpm making it extremely slow. Even by jeep standards.

Any idea of the cause? The catalytic converter has been 100 % hollowed out and there is a brand new MBRP exhaust, so it's not that. There is an exhaust leak of some sort up by the manifold but I don't think that would be it. Any help would be appreciated. Thanks.
 
Get yourself a service manual like Haynes or Chilton's. There will be a Fuel System section with fuel pressure specs that can be checked with a cheap pressure gauge. Start there and spark plugs. Any check engine light codes or strange sounds?
 
I have a 98 the with 225k miles. I have a 4in lift and 35 inch tires but the problem existed well before those add ons all stock. When I accelerate onto the highway, foot on the floor, the jeep won't rev past 3k rpm making it extremely slow. Even by jeep standards.

Any idea of the cause? The catalytic converter has been 100 % hollowed out and there is a brand new MBRP exhaust, so it's not that. There is an exhaust leak of some sort up by the manifold but I don't think that would be it. Any help would be appreciated. Thanks.

Definitely check fuel pressure. I just went through the same thing with my WJ and it ended up being a custom cold air intake I made and the tube was collapsing. Took it off and problem was solved.
 
Best way to check if it's getting air is to pop off the air intake at the throttle body and ensure that the butterfly valve is opening all the way when you press the pedal. Jeep doesn't even have to be on for this. I've seen one on a buddies jeep only open 2/3 of the way which limited the acceleration he could get.

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Thanks for the replys. I will look into these possibilities. Hope it's one of these because they seemike pretty simple fixes!!
 
The butterfly valve on the throttle body is opening fine. This weekend I will be trying to swap out the fuel filter. Regardless if this fixes the issue or not it is probably needed anyway. most likely has never been done before. If that doesn't work I will probably just give up and accept this as a reality until another possibility opens up.
 
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