Need help with P1391 code and misfires

[Outlawpuppy]

Hey all, I need some help tracking down a timing issue I am having with my 1998 4.0 TJ. It has been throwing the p1391 code so I ordered replacement sensors from mopar but neither of the sensors would fit and they told me to kick rocks at the dealer ship due the age/parts being discontinued, I replace both sensors with duralast parts as well as the distributor cap/rotor and plugs but the issue is still persistent. The symptoms besides the code itself is that once the engine hits 2k rpm it starts bucking and misfiring and the problem starts to stop around the 3kish mark. It's bucking so much that it can't be comfortably driven. Please help!! Im at me wits end.

 

[Outlawpuppy]

Hey all, I need some help tracking down a timing issue I am having with my 1998 4.0 TJ. It has been throwing the p1391 code so I ordered replacement sensors from mopar but neither of the sensors would fit and they told me to kick rocks at the dealer ship due the age/parts being discontinued, I replace both sensors with duralast parts as well as the distributor cap/rotor and plugs but the issue is still persistent. The symptoms besides the code itself is that once the engine hits 2k rpm it starts bucking and misfiring and the problem starts to stop around the 3kish mark. It's bucking so much that it can't be comfortably driven. Please help!! Im at me wits end.

It also might be useful information that I have a reasonably large crack in the manifold that I also have to repair but I wanted to fix this problem first. I figured that if it was related then there would be an o2 related code being thrown as well?

 

[Chris]

It also might be useful information that I have a reasonably large crack in the manifold that I also have to repair but I wanted to fix this problem first. I figured that if it was related then there would be an o2 related code being thrown as well?

Are you familiar with Occam's Razor?

Fix the manifold first, that's a major problem that is more than likely the reason for your problems.

 

[Daryl]

Are you familiar with Occam's Razor?

Fix the manifold first, that's a major problem that is more than likely the reason for your problems.

This and reinstall your OEM sensors.

 

[Outlawpuppy]

Are you familiar with Occam's Razor?

Fix the manifold first, that's a major problem that is more than likely the reason for your problems.

Okay, thank you. I will order the parts now. Do you know if it's worth springing for the 500$ banks power header or should I just do the standard 150$ manifold? Tysm

 

[Outlawpuppy]

Nvm, read your post on that topic just now. Thank you guys.