Engine pops, loss of power, smell of fuel
Thread Starter
Junior Member
Joined: Jul 2011
Posts: 84
Likes: 0
From: Blacksburg, VA
Year: 1996
Model: Cherokee
Engine: 4.0L, K&N filter, throttle body riser, Rugged Ridge header
Hey, all!
When I try to accelerate quickly or am going up a hill, my engine makes a series of popping noises accompanied with a sharp drop in RPM and torque, and I can then smell fuel in the cabin (especially if I immediately stop).
Is this some sort of misfiring caused by a faulty fuel pump or injectors?
Thanks!
When I try to accelerate quickly or am going up a hill, my engine makes a series of popping noises accompanied with a sharp drop in RPM and torque, and I can then smell fuel in the cabin (especially if I immediately stop).
Is this some sort of misfiring caused by a faulty fuel pump or injectors?
Thanks!
CF Veteran
Joined: Jun 2011
Posts: 1,023
Likes: 1
From: Southern Idaho
Year: 1994
Model: Cherokee
Engine: 4.0 L/242 CID I-6 High Output MFI
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My mom's old Ford pickup (302 V8) does the same thing at or above 2500 RPMs. It is a misfire, and just started after doing the ignition tune up, so I think one of the spark plugs is bad. I'll be checking for spark soon.
My mom's old Ford pickup (302 V8) does the same thing at or above 2500 RPMs. It is a misfire, and just started after doing the ignition tune up, so I think one of the spark plugs is bad. I'll be checking for spark soon.
CF Veteran




Joined: Nov 2010
Posts: 5,841
Likes: 117
From: In the middle of Minnesota!
Year: 1999
Model: Cherokee
Engine: 4.0
Tuneup hardware should always be reviewed when symptomatic. Never a bad idea.
But something else could be going on here.................
Popping in the intake can indicate a "lean" fuel condition. Backfiring out of the exhaust can indicate a "rich" fuel condition.
My point is that you should check fuel pressure. Must be done with a GAUGE, as anything less is guesswork. For your 96, you should have 49 psi at idle. This is one of the first things that a technician would verify if you were to bring it into a shop. If you don't have one or have access to one, they can be rented from many big box parts stores; call around.
Good luck!
But something else could be going on here.................
Popping in the intake can indicate a "lean" fuel condition. Backfiring out of the exhaust can indicate a "rich" fuel condition.
My point is that you should check fuel pressure. Must be done with a GAUGE, as anything less is guesswork. For your 96, you should have 49 psi at idle. This is one of the first things that a technician would verify if you were to bring it into a shop. If you don't have one or have access to one, they can be rented from many big box parts stores; call around.
Good luck!
CF Veteran
Joined: Jun 2011
Posts: 1,023
Likes: 1
From: Southern Idaho
Year: 1994
Model: Cherokee
Engine: 4.0 L/242 CID I-6 High Output MFI
I forgot to mention that the O2 sensor may need to be replaced... That *could* cause a misfire, because it helps control air/fuel mixture
Thread Starter
Junior Member
Joined: Jul 2011
Posts: 84
Likes: 0
From: Blacksburg, VA
Year: 1996
Model: Cherokee
Engine: 4.0L, K&N filter, throttle body riser, Rugged Ridge header
Thanks for the replies, all! Today I replaced the fuel filter (which sounded like it had loose bits inside of it >_>) and the upstream O2 sensor, and now it runs beautifully.
For now.
:3
For now.
:3
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