Runs like a turd

[Brandon van blair]

When i drive my 2.5L tj 5 speed and give it full throttle is basically cuts off and then wants to die . but at 3/4 throttle it runs fine ... What should i be looking for to fix

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[Chris]

The only way to accurately point you in the right direction would be to scan the vehicle for codes. If it's behaving the way you say it is, the check engine light should be on.

If it is on, go down to your local auto parts store and they'll scan it for free, as well as tell you what codes it's throwing.

It sounds like it could be a throttle position sensor, but again, I'm just guessing since there's no way to tell for sure until you pull the codes.

 

[Jerry Bransford]

The first thing that comes to mind is the fuel pump is no longer able to keep up with the engine at higher RPMs. No guarantees on that of course but if you end up replacing the fuel pump, go with a Bosch fuel pump like you can get on Amazon.com. Avoid at all costs Airtex or Spectre fuel pumps, they don't hold up long at all. Same with cheap store brand fuel pumps like from Autozone. Replacing the fuel pump is a difficult enough job (the gas tank has to be dropped) that you don't want to have to do it twice in the first year or two because the replacement fuel pump failed prematurely.

No guarantees it's a bad or weak fuel pump but that's my first guess.

Here's a way to verify if the pump is good or not... your fuel injector's fuel rail has a pressure test port on it you can screw a fuel pressure gauge onto that you can rent or borrow for free from most auto parts stores like Autozone. The fuel pressure is supposed to be very close to 49 psi. See what the fuel pressure is at idle then rev the engine up high enough that it would start to die and see if the fuel pump is still putting out close to 49 psi. The fuel pressure test port looks like a big oversized tire valve stem, it has a protective plastic cap screwed over the top of it.

 

[Brandon van blair]

Iv had the codes done and it throws out the o2 sensors.. Replaced the upper and the lower has a dummy plug due to after market exhuast . iv replaced all sensor's and still does it . fuel pump was my next guess. But didnt know if it would b easier to replace just the filter due to it may b clogged

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[Jerry Bransford]

The main fuel filter is located inside the fuel pressure regulator that sits on top of the fuel pump, external to the tank. The tank would have to be dropped to replace it, like has to be done to replace the fuel pump.

This is the fuel pressure regulator that the TJ's main fuel filter is located inside of...

The TJ's fuel filter has an absolutely huge surface area and is considered by the factory to be a lifetime part... as evidenced by it not being simple to replace as the old inline fuel filters were in older cars like I grew up with.

I'd suspect almost anything else before suspecting a clogged factory fuel filter.

 

[Ahoragi]

This is good info. I'm about to swap out my gas tank skid since it's rusted 3/4 of the way across and wanted to do the pump while I was at it. Bosch it is....