TJ 4.0 cutting out at 2250 RPM

DavidPLindsey

Member
Joined
Mar 5, 2022
Messages
50
Location
Franklinton, La.
My Jeep rubicon unlimited is cutting out at 2250 rpms (like it had a rev. limiter). Then after you have a long start, run it (below 2250) for a while, turn it off, wait a couple of seconds, restart, it will run perfect, power and revs. I have replaced, cam sensor, then the oil pump drive unit (that use to be called the distributor), then the crank sensor, then the o2 sensors, syncronized them, then the timing chain and gears, synchronized them again, Worked a little while (20 miles) with the engine light off (first time in 50,000 miles), then the engine light came back on and long starts every other time. Engine light stays on. I am not ready to get rid of the unicorn of jeeps because It still serves reliable back and forth to town (if you drive like I do) and that is rare with any vehicle. If someone has a revelation from above please pass it on to me, or I will not drive over 65 miles an hour.(4.0 automatic) if that helps. May God Bless and fix, DL.
 
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First , if it has a CEL there is a code - we need to know the code.

Second, @Wranglerfix has been notified, be prepared to buy a PCM if he recommends it. He drives an even rarer Unicorn, and knows his stuff.
 
If the 2250 rpms is under load then you might be starving it for fuel. Clogged fuel filter or weak fuel pump.
 
If the 2250 rpms is under load then you might be starving it for fuel. Clogged fuel filter or week fuel pump.
It could be a bad fuel pump but I'd never suspect a clogged fuel filter unless it was being gassed up in a third-world country. The TJ's fuel filter is not an old-fashioned in-line fuel filter like I grew up in the 60's that needed to be cleaned out regularly. The TJ's fuel filter has an absolutely HUGE surface area and is considered to be a lifetime filter. Not to mention the fuel filter very difficult to change, it's inside the fuel pressure regulator enclosure which requires the gas tank be dropped to get to it. The factory put it there since they don't expect it to ever need to be changed. The fuel we put into our gas tanks here in the US is extremely well filtered.
 
It could be a bad fuel pump but I'd never suspect a clogged fuel filter unless it was being gassed up in a third-world country. The TJ's fuel filter is not an old-fashioned in-line fuel filter like I grew up in the 60's that needed to be cleaned out regularly. The TJ's fuel filter has an absolutely HUGE surface area and is considered to be a lifetime filter. Not to mention the fuel filter very difficult to change, it's inside the fuel pressure regulator enclosure which requires the gas tank be dropped to get to it. The factory put it there since they don't expect it to ever need to be changed. The fuel we put into our gas tanks here in the US is extremely well filtered.
Im with Jerry, fuel contamination is practically nil-

This may be very irrelevant- I had a work van sit at a dealer ship shop for nearly 2 months- turned out to be a deteriorated pick up hose in the tank -

The rpm make me think pcm 🙄
 
Im with Jerry, fuel contamination is practically nil-

This may be very irrelevant- I had a work van sit at a dealer ship shop for nearly 2 months- turned out to be a deteriorated pick up hose in the tank -

The rpm make me think pcm 🙄
But, I will give credit to the PCM mod. being that was my next Guess. But at 700.00 I'm slow at guessing and wondered about flashing (auto shock treatment)
 
See I have made many readings, and this is my first forum. (Yes, signs of desperation.
Ok good to know it's a 2006, 2005 and 2006 engine computers are known to have problems. Mark @Wranglerfix is a PCM (engine computer) guru and he can give you an idea if it could be PCM related. That his wranglerfix company name was highlighted twice in this thread means he was alerted to your thread here. His website is www.wranglerfix.com

And you can generate your Rubicon's codes using its built-in code reader. Simply turn the ignition switch on-off-on three times within five seconds and leave it in the on position. Give the diagnostics several second to run, eventually any stored trouble codes will start displaying in the odometer. Like P1234. If there are no stored trouble codes it will at least say 'DONE' if you did it right.
 
It could be a bad fuel pump but I'd never suspect a clogged fuel filter unless it was being gassed up in a third-world country. The TJ's fuel filter is not an old-fashioned in-line fuel filter like I grew up in the 60's that needed to be cleaned out regularly. The TJ's fuel filter has an absolutely HUGE surface area and is considered to be a lifetime filter. Not to mention the fuel filter very difficult to change, it's inside the fuel pressure regulator enclosure which requires the gas tank be dropped to get to it. The factory put it there since they don't expect it to ever need to be changed. The fuel we put into our gas tanks here in the US is extremely well filtered.
You are so right and had I joined sooner you may have saved me the burden and cost of the fuel pump but all I can say now AMEN!
 
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Ok good to know it's a 2006, 2005 and 2006 engine computers are known to have problems. Mark @Wranglerfix is a PCM (engine computer) guru and he can give you an idea if it could be PCM related. That his wranglerfix company name was highlighted twice in this thread means he was alerted to your thread here. His website is www.wranglerfix.com

And you can generate your Rubicon's codes using its built-in code reader. Simply turn the ignition switch on-off-on three times within five seconds and leave it in the on position. Give the diagnostics several second to run, eventually any stored trouble codes will start displaying in the odometer. Like P1234. If there are no stored trouble codes it will at least say 'DONE' if you did it right.
You see already learned something in my first day on the forum. Bless you, the code is P0344. Must be the new language I refuse to learn or Greek. But With a code book or goggle I'll see. Back from goggle been there done it and got the sweatshirt. (learning the hard way) As far as wiring my jeep has been garaged, no mud riding, driven by only me unless my wife is real good, and serviced regular.
 
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P 0344, replaced and sync. twice, Thank You though and appreciate the time and brain matter.
That's a code indicating a problem with the camshaft position sensor, located on the passenger-side of the engine atop the shaft that used to have a distributor on top of it. Does the above comment mean you already replaced it?
 
Did you use a Mopar cam sensor? If not try that, if that doesn’t work, you may have a PCM problem.

If you bought a crown OPDA, that sensor that comes on it is well known for problems.
I understand about quality, I tried 2 cam sensors, Then my tech. (son in law) said all my sensors where reading out on his computer. Second, I am glad (with todays supply and work standards) to get any sensor. Not like we are blessed with many choices through the decisions of our fearless, (fearful) leaders.