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sprinkles08
sprinkles08, ASE Certified Technician
Category: UK Car
Satisfied Customers: 22114
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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Moparfl, I own a jeep liberty 2008. a malfunction code P0138

Customer Question

hi moparfl, I'm Al, I own a jeep liberty 2008. a malfunction code P0138 keep coming. I replaced the O2 sensors , it was ok for month ,with no malfunction light, but still the car engine seems to hesitate,when i push the gas pedal hard.
I replaced sparkplugs,cordwire,EGR sensor and PCV hose
but still problem exsits.
Thankyou.
Submitted: 1 year ago.
Category: UK Car
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

Where did the replacement sensors come from?

Customer: replied 1 year ago.
It was replaced in the jeep dealer garage in my country Oman(o2 sensors),
The other parts was replaced in jeep dealer garage in U.A.E.
The jeep dealers in uae and oman use MOPAR spare parts.
Expert:  sprinkles08 replied 1 year ago.

It was fine for a month and then the P0138 set again?

Customer: replied 1 year ago.
but even without the malfunction light,the car engine hesitate when i push the gas pedal hard,when this happens the malfunction light comes and dissapear after 3 sec,i checked it with my obd scanner it was p0300, but just 3 days ago malfunction light remained with the p0138 code.
Expert:  sprinkles08 replied 1 year ago.

Does it run rough during warmup, at idle or low speeds, or will it also happen while driving at higher speeds?

Customer: replied 1 year ago.
it only runs rough at higher speeds,
this morning I was driving In speed of 120km\h, then I pushed gas pedal to accelerate, the engine refused to respond,malfunction light kept blinking,so i slowed down,and keep pushing the gas pedal slowly.idle or low speeds it is ok.
Expert:  sprinkles08 replied 1 year ago.

Has fuel pressure been checked under a load when it's running poorly?

Customer: replied 1 year ago.
No
Customer: replied 1 year ago.
How can I check it?
Expert:  sprinkles08 replied 1 year ago.

A fuel pressure gauge would need to be connected and then the vehicle driven while monitoring pressure.

Customer: replied 1 year ago.
There one more point i need to mention,
When i push the gas pedal hard to accelerate , a sound comes from under hood,it seems like it is coming from left side,near front wheel ,like air sound.
Expert:  sprinkles08 replied 1 year ago.

Is it a hissing or humming type sound?

Customer: replied 1 year ago.
It is like hissing sound.
Expert:  sprinkles08 replied 1 year ago.

A hiss on acceleration from that area is likely from a restricted catalytic converter. The material inside the converters can break up and the pieces can migrate around and block exhaust flow. I would recommend having a backpressure test done on that bank and I believe you'll find the converter is restricted.

Customer: replied 1 year ago.
3 codes came:
P0303
P0001
P3800,P0138 didn't appear today
Customer: replied 1 year ago.
I did OBD scan this morning,
3 codes came:
P0303
P0001
P3800,
P0138 didn't appear today
Expert:  sprinkles08 replied 1 year ago.

P0303 is a cylinder 3 misfire, the other two aren't valid.

Customer: replied 1 year ago.
hi,
I am planning to take my car to garage this weekend ,is there any other tests to do other than fuel pressure test,
or malfunctions to consider other than catalytic converter malfunction?Thank you,
Expert:  sprinkles08 replied 1 year ago.

What needs to be done is test backpressure on the left bank to check for a catalytic converter restriction. The missing on that bank along with the hiss points to a restricted converter.