Motor falls on its face... Sometimes
06-18-2012, 08:09 PM
#1
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Year: 98
Model: Cherokee
Engine: 4.0
Motor falls on its face... Sometimes
Ok here we go i have been chasing this problem for a few months now!
First i have a 98 xj both my o2 sensors unpluged as of right now.
So when i have everything all pluged in i can let it idle till it warms up and then it starts to bog down to like 300-500 rpm and shoots back up like a surge of gas but then it goes back down to 300 and surges back and forth. If i hit the gas it will be fine for a min and back to ****! When i shut it off and turn it back on it will run fine for a lil while.
When i am driving it does the same thing but if i hit the gas it will get a big surge and run fine for a while! I also hear a backfire that sounds like it is comming through my intake.
I also not to long ago had my cat removed cause it was blown out. Now its just straight pipe to muffler.
I have replaced:
Ok with all that said i have unpluged both of my 02 sensors and it runes fine! No bogging no back fire
Before i unpluged them i had both of them replaced and right after (maybe a few days later) it would through a code for bad o2. Sometimes it would say short to o2 bank 2 sensor.
Please help me i am running really rich and gas is killing me!
Text me if need be!
Mike
734-732-6009
First i have a 98 xj both my o2 sensors unpluged as of right now.
So when i have everything all pluged in i can let it idle till it warms up and then it starts to bog down to like 300-500 rpm and shoots back up like a surge of gas but then it goes back down to 300 and surges back and forth. If i hit the gas it will be fine for a min and back to ****! When i shut it off and turn it back on it will run fine for a lil while.
When i am driving it does the same thing but if i hit the gas it will get a big surge and run fine for a while! I also hear a backfire that sounds like it is comming through my intake.
I also not to long ago had my cat removed cause it was blown out. Now its just straight pipe to muffler.
I have replaced:
- IAC
- Map sensor
- coolant temp sensor
- TPS
- Plugs
- Wires
Ok with all that said i have unpluged both of my 02 sensors and it runes fine! No bogging no back fire
Before i unpluged them i had both of them replaced and right after (maybe a few days later) it would through a code for bad o2. Sometimes it would say short to o2 bank 2 sensor.
Please help me i am running really rich and gas is killing me!
Text me if need be!
Mike
734-732-6009
06-18-2012, 08:18 PM
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06-19-2012, 06:09 PM
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Back firing thru the intake means too much fuel is being dumped into the engine, so it could point to the O2, Also check all the wires for the o2 sensors to make sure they are not shorting to the exhaust or something.
edit: from 1st hand experiance the cat wouldnt affect this unless its clogged, which is smart to remove it temporarily to eliminate that cause.
edit: from 1st hand experiance the cat wouldnt affect this unless its clogged, which is smart to remove it temporarily to eliminate that cause.
Last edited by TheJerm; 06-19-2012 at 06:11 PM.
06-19-2012, 06:16 PM
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Year: 98
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Originally Posted by TheJerm
Back firing thru the intake means too much fuel is being dumped into the engine, so it could point to the O2, Also check all the wires for the o2 sensors to make sure they are not shorting to the exhaust or something.
edit: from 1st hand experiance the cat wouldnt affect this unless its clogged, which is smart to remove it temporarily to eliminate that cause.
edit: from 1st hand experiance the cat wouldnt affect this unless its clogged, which is smart to remove it temporarily to eliminate that cause.
06-19-2012, 06:18 PM
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Year: 1996
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Engine: 4.0 HO Straight Six
Back up... You say your o2 sensor is throwing a code... And it bogs and backfires when the o2 sensor is plugged in... HMMMM!!!
Try rockauto.com. NTK o2 sensors are the way to go.
Try rockauto.com. NTK o2 sensors are the way to go.
06-19-2012, 06:28 PM
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Year: 1995
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FYI crank position sensor is on the bellhousing on the driver side, should see wires running off the back of the intake down to it. Cam sensor is in the distributor, you'll see the small wires running to it. But I dont think this is your issue. I too have bosch O2 sensors and never had issues but you never know
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