cylinder 6 misfire
CF Veteran
Joined: Sep 2009
Posts: 8,567
Likes: 20
From: ☼ Blackhole Sun
Year: My Jeep is a GMC
^
Hitting the catalytic convertor with ones hand usually results in a sore hand. Try something a little more scientific instead:
Here's a simple do it yourself (DIY) test that can be performed to see if your CAT convertor is clogged or if you have excessive exhaust system backpressure or restriction:
Tools needed: vacuum gauge, tee connector
Connect a standard engine vacuum gage into a vacuum port off the intake system. You can tee off the fuel pressure regulator or purge valve lines located on the engine.
Start engine and maintain rpms at 2000 - 2500 rpm.
Watch vacuum gauge and reading should stabilize and stay steady.
If vacuum reading starts dropping or decreasing, it indicates either a clogged CAT convertor or restriction/backpressure in the exhaust system.
Hitting the catalytic convertor with ones hand usually results in a sore hand. Try something a little more scientific instead:
Here's a simple do it yourself (DIY) test that can be performed to see if your CAT convertor is clogged or if you have excessive exhaust system backpressure or restriction:
Tools needed: vacuum gauge, tee connector
Connect a standard engine vacuum gage into a vacuum port off the intake system. You can tee off the fuel pressure regulator or purge valve lines located on the engine.
Start engine and maintain rpms at 2000 - 2500 rpm.
Watch vacuum gauge and reading should stabilize and stay steady.
If vacuum reading starts dropping or decreasing, it indicates either a clogged CAT convertor or restriction/backpressure in the exhaust system.
Thread Starter
Junior Member
Joined: Jul 2013
Posts: 70
Likes: 0
From: Long Island
Year: 2001
Model: Cherokee
Engine: 4.0 6 cylinder
Alright guys, thanks for all the help
poured seafoam in the intake to clean up possible clogged injectors, changed all plugs, and finally got the darn oxygen sensor off and replaced it with a new one.
After this my check engine light was on, but as i read that this is common when you change an oxygen sensor, so after some research I read that you can 'reset' the system which will acknowledge the new O2 sensor by resetting the ECU, which I found how to do 'the dealer way' on the forum.
No check engine light, no jerking, jeep is running smooth and I went from a pathetic 8 mpg to 16 mpg
Once again, thank you all for your help, without you this jeep would surely be dead
poured seafoam in the intake to clean up possible clogged injectors, changed all plugs, and finally got the darn oxygen sensor off and replaced it with a new one.
After this my check engine light was on, but as i read that this is common when you change an oxygen sensor, so after some research I read that you can 'reset' the system which will acknowledge the new O2 sensor by resetting the ECU, which I found how to do 'the dealer way' on the forum.
No check engine light, no jerking, jeep is running smooth and I went from a pathetic 8 mpg to 16 mpg
Once again, thank you all for your help, without you this jeep would surely be dead
Junior Member
Joined: Feb 2014
Posts: 89
Likes: 1
From: VA
Year: 2000
Model: Cherokee
Engine: 4.0
Alright guys, thanks for all the help
poured seafoam in the intake to clean up possible clogged injectors, changed all plugs, and finally got the darn oxygen sensor off and replaced it with a new one.
After this my check engine light was on, but as i read that this is common when you change an oxygen sensor, so after some research I read that you can 'reset' the system which will acknowledge the new O2 sensor by resetting the ECU, which I found how to do 'the dealer way' on the forum.
No check engine light, no jerking, jeep is running smooth and I went from a pathetic 8 mpg to 16 mpg
Once again, thank you all for your help, without you this jeep would surely be dead
poured seafoam in the intake to clean up possible clogged injectors, changed all plugs, and finally got the darn oxygen sensor off and replaced it with a new one.
After this my check engine light was on, but as i read that this is common when you change an oxygen sensor, so after some research I read that you can 'reset' the system which will acknowledge the new O2 sensor by resetting the ECU, which I found how to do 'the dealer way' on the forum.
No check engine light, no jerking, jeep is running smooth and I went from a pathetic 8 mpg to 16 mpg
Once again, thank you all for your help, without you this jeep would surely be dead
Newbie
Joined: Aug 2011
Posts: 10
Likes: 0
From: Rochester
Year: 2001
Model: Grand Cherokee
Engine: straight 6, 4 liter
2001 JGC 4.0 liter P0158 code on California Emmissions
^
Hitting the catalytic convertor with ones hand usually results in a sore hand. Try something a little more scientific instead:
Here's a simple do it yourself (DIY) test that can be performed to see if your CAT convertor is clogged or if you have excessive exhaust system backpressure or restriction:
Tools needed: vacuum gauge, tee connector
Connect a standard engine vacuum gage into a vacuum port off the intake system. You can tee off the fuel pressure regulator or purge valve lines located on the engine.
Start engine and maintain rpms at 2000 - 2500 rpm.
Watch vacuum gauge and reading should stabilize and stay steady.
If vacuum reading starts dropping or decreasing, it indicates either a clogged CAT convertor or restriction/backpressure in the exhaust system.
Hitting the catalytic convertor with ones hand usually results in a sore hand. Try something a little more scientific instead:
Here's a simple do it yourself (DIY) test that can be performed to see if your CAT convertor is clogged or if you have excessive exhaust system backpressure or restriction:
Tools needed: vacuum gauge, tee connector
Connect a standard engine vacuum gage into a vacuum port off the intake system. You can tee off the fuel pressure regulator or purge valve lines located on the engine.
Start engine and maintain rpms at 2000 - 2500 rpm.
Watch vacuum gauge and reading should stabilize and stay steady.
If vacuum reading starts dropping or decreasing, it indicates either a clogged CAT convertor or restriction/backpressure in the exhaust system.
So I connect to ANY vacuum port off the intake system ?
TEE OFF the fuel pressure regulator ??? Or purge valve lines located on the engine ??? Is there a video I can watch about how this is done? I can't find one on YouTube. Or can you be more descriptive in your explanation?
Thanks
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