Turns over but will not run and back fires

MARY SNELLINGS

MEMBER
2012 JEEP LIBERTY
3.7L
V6
4WD
1,190,000 MILES

It is back firing so I replaced spark plugs, spark plug wires, and coils, and it will not stay running now and the mileage is one hundred nineteen thousand.

Saturday, May 20th, 2017 AT 6:04 AM

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,186 POSTS

Hello,

It sounds like there might be a mechanical issue inside the engine, the best way to check the engine is with a compression test.

Here is a guide to help you check the engine and show us if there is any problems so we can go from there.

https://www.2carpros.com/articles/how-to-test-engine-compression

You can rent a gauge from the auto parts store for free.

Please run this test and get back to us so we can continue helping you.

Cheers, Ken

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Monday, May 22nd, 2017 AT 11:12 AM

JAYH9673

MEMBER
1 POST
2002 JEEP LIBERTY
4 CYL
2WD
MANUAL
65,000 MILES

Engine Performance problem
2002 Jeep Liberty 4 cyl Two Wheel Drive Manual 65,000 miles

My Jeep Liberty sport runs pretty good. Only at times does it hesitate and backfire from inside the engine compartment on the passenger side. For instance, i'll be traveling in 3rd gear (manual) at 35-40 and switch to 5th and it hesitates and backfires. I changed the plugs and everything was fine for about 2 months when it started doing this. When i'm in neutral and tap the accelerator pedal and rev engine, I hear what sounds like engine sucking a bunch of air. Could it be a intake manifold gasket?

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Monday, May 22nd, 2017 AT 11:12 AM (Merged)

RASMATAZ

MECHANIC
75,992 POSTS

Inspect it for vacuum leaks if none do below

Inspect and test all the following listed below:

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard

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Monday, May 22nd, 2017 AT 11:13 AM (Merged)

ERIC 1969

MEMBER
1 POST
2005 JEEP LIBERTY
192,000 MILES

Ok was having a starter problom Got it home with engine light. Went to crank it and boom my father said it backfire but smoke came from under the hood so I but the starter and put it on crunk it up and it rears up high rpms to 5 to 4 fluctuation the it cuts off I don't know the problem need help please

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Monday, May 22nd, 2017 AT 11:13 AM (Merged)