Sputtering issue

[Witchy Woman]

I have a 97 TJ, 4.0, with a 5 speed. I have recently developed an issue that my repair shop can't duplicate (when they have it), thus can't repair it. Problem: Jeep starts and runs fine on initial start up. You drive it (say to the store, it takes 15 minutes) shut the vehicle off, let it sits (15 minutes to 1/2 hour), restart it and drive away. Here's where the problem comes in. As you accelerate in 1st gear all is fine, shift to 2nd gear and the vehicle starts sputtering and bucking. If you depress the clutch, push down on the accelerator and let up, the problem clears.

The vehicle has been in the shop (a noted Jeep repair facility in my area) three separate times. They have test the electrical and fuel systems. They have used it to run parts in effort to duplicate the issue. They can't seem to get it to act up. The throttle position sensor has been replaced, connections at the coil and crank sensor have been checked, cleaned and tightened. Fuel pressure has been checked, both at idle and under driving conditions.

This is an annoyance to say the least! Any and all help in resolving this issue is greatly appreciated.

Contact: [email protected]
[email protected]

 

[97JadeTJ]

My 97 2.5 L auto was acting up similar to that when I bought it… It might drive fine for 5 -10 even 15 minutes and then all of a sudden start bucking and trying to die and then it would run fine again… I traced it down to a non Mopar O2 sensor… I replaced the O2 sensors with NTG sensors and I’ve never had the problem since…

 

[Witchy Woman]

My 97 2.5 L auto was acting up similar to that when I bought it… It might drive fine for 5 -10 even 15 minutes and then all of a sudden start bucking and trying to die and then it would run fine again… I traced it down to a non Mopar O2 sensor… I replaced the O2 sensors with NTG sensors and I’ve never had the problem since…

Thanks for the reply. I'm going to update my code reader and see if it gives me any new insight. The O2 sensor is cheap enough and probably due to be changed anyway. I'll give it a try.

 

[macleanflood]

Exhaust leak maybe? Anyone check for cracked headers?

What kind of MPG are you getting? I was getting 9-10 on an exhaust leak and 12-14 without...the O2 sensor can't do its job without all the exhaust.

Any misfire codes? Check fuel pressure on the Schrader valve on the fuel rail? How does it start...quick or a couple of cranks or more?

-Mac

 

[97JadeTJ]

Thanks for the reply. I'm going to update my code reader and see if it gives me any new insight. The O2 sensor is cheap enough and probably due to be changed anyway. I'll give it a try.

Make sure you use the NTG or NTK sensors because they are OEM… Shop brands tend to cause problems with TJ’s…