Great Lakes 4x4. The largest offroad forum in the Midwest banner
1 - 7 of 7 Posts

·
Support the Sport!
Joined
·
2,015 Posts
Discussion Starter · #1 ·
My cousin has a 01 or an 02 GMC seirra with the 5.3L in it and he is getting a misfire on Cylinder number 6. Can anyone tell me which cylinder is number 6? He'd like to try swapping some plugs or wires around to narrow down the problem.

About 5 months ago, he had some sort of gasket replaced which apparently a common cause of the problem. he also had a new CAT put in and the problem cleared up. He'd like to know if it's the same problem before he goes back to the repair shop.

thanks.
 

·
circling the drain
Joined
·
35,863 Posts
6 should be passenger side third to the back.

run his codes, last time I had a misfire on a 5.3 it was bad o2 sensor. Even the autozone code readers can tell you which of the four o2 sensors are bad on that motor.
 

·
Visiting Admin
Joined
·
9,065 Posts
also a cheap scanner like the crap they use at auto zone thats like the default reading for any thing that it cant read
 

·
Registered
Joined
·
6 Posts
need help

i have a 99 chevy silverado 1500 with a 5.3L and i am getting a misfire on cylinders 2 4 6 and 8 its one hole bank and i have no idea whats going on with? i just dont want to have to keep money into it and not have it fix it if someone can point me in the right direction would be great or if this has happed to someone elce and could tell me how to fix the problem or what the problem is.i also was tld it could be the catalytic converter on that side??????
 

·
Registered
Joined
·
5,329 Posts
i have a 99 chevy silverado 1500 with a 5.3L and i am getting a misfire on cylinders 2 4 6 and 8 its one hole bank and i have no idea whats going on with? i just dont want to have to keep money into it and not have it fix it if someone can point me in the right direction would be great or if this has happed to someone elce and could tell me how to fix the problem or what the problem is.i also was tld it could be the catalytic converter on that side??????

misfiring on all banks on one side, wonder if the o2 sensor is reading rich
 

·
Registered
Joined
·
38 Posts
To both people with problems...

Poster 1 with #6 misfire...

Try swapping coils with one that is Not misfiring and see if it moves, if so, it's the coil. If not, check the coil harness plug. It could be damaged. If everything checks out such as that, pull the valve cover and check the valve spring, push rod and rocker arm. Ls engines have a tendency to bend push rods if over revved. Another common problem with the ls engines is the needle bearings in the rocker arms. They will come apart and send them all over the engine. This can cause a miss. However, 9 times out of 10, they will collect in the pan and stay put. They are too big to end up in the oil pump.

If all that checks out, get a noid light on the injector. It might be sticking open and flooding the cylinder, putting the fire out.

If all else fails, check the condition of the cylinder. The easiest way is to do a compression test and leak down test. You may have a valve hanging open because of carbon build up or you may have a busted piston.

To the other guy with an entire bank missing, you either have a bad coil harness/connector or injector harness. Also, you could have a bad o2 or plugged cat.
 
1 - 7 of 7 Posts
Top