Why does my 96 Jeep Grand Cherokee Laredo 4.0 spit and sputter when going uphill?

[Sstowe333]

It happens off and on but more often on a 1/4 tank of gas. If anyone has any suggestions on how to fix it please let me know

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[k-2]

how much grade to that hill?
Anyway I would scan for codes*, and do a fuel pressure test - maybe jack up front of jeep to simulate. I suspect a fuel pump issue, we will need to inspect and replace, use a jeep pump aftermarket pumps are not recommended.

*I would expect lean codes....

 

[Sstowe333]

Thank you so much you are amazing and not much of a grade at all it can be as small as going up an overpass. Where are you located ? And how much do you charge?

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[Sstowe333]

how much grade to that hill?
Anyway I would scan for codes*, and do a fuel pressure test - maybe jack up front of jeep to simulate. I suspect a fuel pump issue, we will need to inspect and replace, use a jeep pump aftermarket pumps are not recommended.

*I would expect lean codes....

?

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[JPNinPA]

Try cleaning the TB and IAC. You should do this every 30-50k mi. Check the connection to the TPS.
Run some injector cleaner through.
Check fuel pressure at idle and at 2k rpm. Should be constant and if I recall 49 +/-2 psi.


JPNinPA
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[Sstowe333]

Try cleaning the TB and IAC. You should do this every 30-50k mi. Check the connection to the TPS.
Run some injector cleaner through.
Check fuel pressure at idle and at 2k rpm. Should be constant and if I recall 49 +/-2 psi.


JPNinPA
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Thank you so much I will try everything !

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[JPNinPA]

What rpm do you idle at?


JPNinPA
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[Sstowe333]

I think 900rpms its just under 1000 rpms

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[Sstowe333]

how much grade to that hill?
Anyway I would scan for codes*, and do a fuel pressure test - maybe jack up front of jeep to simulate. I suspect a fuel pump issue, we will need to inspect and replace, use a jeep pump aftermarket pumps are not recommended.

*I would expect lean codes....

Thank you so much i will try all that

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[Sstowe333]

What rpm do you idle at?


JPNinPA
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Just under 1000 rpm i think 900

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[JPNinPA]

Clean the TB and IAC as mentioned. The high idle is a sign of a vac leak between the bottom of the TB and the cylinder. While idling spray tb cleaner or wd40 on each opening in the intake. Vac lines, fuel injectors ... when the idle changes you found your leak. In some cases the leak is due to a loose intake or cracked vac line and change how much air is leaking in. The lean mixture can lead to the sputtering.


Also running some fuel injector cleaner. (Edit: Tectron not Rislone) in the tank.

Lastly dirty valves can cause issues. Running your engine above 3300 rpm for a period allows the valves to rotate and reduces the chance of carbon buildup. To clean the carbon off valves you could use sea foam or water. If you want to do either ask how or search. You need to follow a specific process.

JPNinPA
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[JPNinPA]

Clean the TB and IAC as mentioned. The high idle is a sign of a vac leak between the bottom of the TB and the cylinder. While idling spray tb cleaner or wd40 on each opening in the intake. Vac lines, fuel injectors ... when the idle changes you found your leak. In some cases the leak is due to a loose intake or cracked vac line and change how much air is leaking in. The lean mixture can lead to the sputtering.


Also running some fuel injector cleaner. (edit:Tectron. Not Rislone) in the tank.

Lastly dirty valves can cause issues. Running your engine above 3300 rpm for a period allows the valves to rotate and reduces the chance of carbon buildup. To clean the carbon off valves you could use sea foam or water. If you want to do either ask how or search. You need to follow a specific process.

JPNinPA
Using Jeepz.com app

Regards,
JPNinPA

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