07 JK engine hesitation

Toxicity JK

Toxicity JK

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Joined
Aug 9, 2023
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5
Location
Palm Bay Florida
07 JK 3.8 V6 automatic. SO lets start by detailing what the Jeep is doing. It has developed a hesitation for lack of a better word (almost feels like a misfire, but is not causing a code). The hesitation seems pretty random as it doesn't occur at the same RPM or just on acceleration. Along with the hesitation when driving, it also has an intermittent rough idle and will occasionally die when at idle. Again no discernable pattern to it seems to be almost completely random. Another odd factor is i thought it could be dirty injectors so I ran 2 cans of Seafoam through it. Both times it ran perfectly for the first 2/3 of the tank then started doing it again and got worse in the last 1/3 as the fuel level got lower.
What I have already done/replaced
MAP sensor
PCV valve
plugs
plug wires
cleaned throttle body
All of these seemed to help the engine run quieter and smoother until the random hesitation.
The latest twist to this tale is yesterday the gas cap warning came on and will not go off even after replacing the gas cap.

Any ideas? fuel injectors? Fuel pump filter screen?
 
Toxicity JK said:
Also forget to mention it will do the hesitation when I hit a bump also. Don't know if this points to anything in particular or just another crazy symptom.
Click to expand...

Any update ?
Was on a road trip just over a week ago . Noticed this happened a couple times .
On the HWY Sunday and was doing it again just as you described . No issues at idle .
At HWY speeds going uphill the odd hesitation
Purchased new plugs couple months ago . Haven’t installed yet . Ordering new wires & Coil Pack. No idea when these were replaced if ever so hoping it will solve issue .
Noticed in your original post coil pack wasn’t replaced .
Maybe that’s the issue ?
 
Speartip said:
Any update ?
Was on a road trip just over a week ago . Noticed this happened a couple times .
On the HWY Sunday and was doing it again just as you described . No issues at idle .
At HWY speeds going uphill the odd hesitation
Purchased new plugs couple months ago . Haven’t installed yet . Ordering new wires & Coil Pack. No idea when these were replaced if ever so hoping it will solve issue .
Noticed in your original post coil pack wasn’t replaced .
Maybe that’s the issue ?
Click to expand...

Maybe your under hood insulation getting sucked over the air intake tube.
 
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I had a similar problem. JK would run fine then Rough idle and Jk would die randomly without codes. Put in a new fuel pump but didn't fix it. I ended up having it checked by our local Jeep dealer who found the problem was a broken wire inside one of the connectors where it plugs into the fuse bank. He soldered the wire directly and no more problems. It seems every bounce would just shut off the fuel system and jeep would die.
 
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hdivr said:
I had a similar problem. JK would run fine then Rough idle and Jk would die randomly without codes. Put in a new fuel pump but didn't fix it. I ended up having it checked by our local Jeep dealer who found the problem was a broken wire inside one of the connectors where it plugs into the fuse bank. He soldered the wire directly and no more problems. It seems every bounce would just shut off the fuel system and jeep would die.
Click to expand...
Very interesting. Do you know which wire it was? I am having the hesitation issue when I hit a bump.
 
Speartip said:
Any update ?
Was on a road trip just over a week ago . Noticed this happened a couple times .
On the HWY Sunday and was doing it again just as you described . No issues at idle .
At HWY speeds going uphill the odd hesitation
Purchased new plugs couple months ago . Haven’t installed yet . Ordering new wires & Coil Pack. No idea when these were replaced if ever so hoping it will solve issue .
Noticed in your original post coil pack wasn’t replaced .
Maybe that’s the issue ?
Click to expand...
Still no solution. Coil pack was replaced last week. developed a misfire on cylinder 1 so I thought it was the culmination of the hesitation issue. Replaced the coil pack and it fixed the constant cylinder 1 misfire but the hesitation issue continued. I'm down to fuel pump, EGR valve, or wiring issue somewhere. All are relatively inexpensive parts but pains to replace.
 
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hdivr said:
I had a similar problem. JK would run fine then Rough idle and Jk would die randomly without codes. Put in a new fuel pump but didn't fix it. I ended up having it checked by our local Jeep dealer who found the problem was a broken wire inside one of the connectors where it plugs into the fuse bank. He soldered the wire directly and no more problems. It seems every bounce would just shut off the fuel system and jeep would die.
Click to expand...

That's good Intel . Thanks. Bumps don't effect my hesitation .
 
Toxicity JK said:
Still no solution. Coil pack was replaced last week. developed a misfire on cylinder 1 so I thought it was the culmination of the hesitation issue. Replaced the coil pack and it fixed the constant cylinder 1 misfire but the hesitation issue continued. I'm down to fuel pump, EGR valve, or wiring issue somewhere. All are relatively inexpensive parts but pains to replace.
Click to expand...

Ok . Keep us in the loop if you wouldnt mind.
I will report back if my plug, wire, coil pack
helps my situation .
 
Update .
Plugged in JSCaN today and intermittent code I was getting
P0430. Catalyst system efficiency below threshold .

Doing some research issues such as O2 sensor , misfire or fuel pump problem can cause a P0430 code .

Installed new plugs , coil pack & wires . Runs really smooth .
Hesitation I was getting is gone .

At start up after replacing components check engine light turned off .
Not sure if checking code eliminated warning or if issue is resolved .
Drove it for an hour with no warnings and was really smooth across the all RPM bands.
 
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Had a similar issue on a 08. Check the grounds for your knock sensor and O2 sensors. They attach at the bottom of the passenger side of the engine block.
 
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JonBoehman said:
Had a similar issue on a 08. Check the grounds for your knock sensor and O2 sensors. They attach at the bottom of the passenger side of the engine block.
Click to expand...

Took the Jeep on Hwy for a couple hours on Sunday
Still having issues . I was kinda thinking 02 sensors as well . Doing some research there is 4 on the exhaust .
2 on each side before & after catalytic converter
Check engine light came on again today as well. Will jscan it again tomorrow .
Which codes were you getting ? 02 or catalytic converter .
Thing is when I checked didn’t have a 02 code?
Pricing out catalytic converters. It can be pricey .
Found a inexpensive setup on Amazon .
That’s the confusing thing with a P0430 code. It’s not necessarily the catalytic converter . Could be ignition , fuel or sensor . Or the cat ?
Think what I will do is the sensors first . If that doesn’t rectify issue probably bring it in for a more intensive diagnostic .
 
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