3 Misfiring Cyls On A Gmc Jimmy

[Scrobo]

Hey everyone.

 

Truck in question:

1999 GMC Jimmy SLT

4DR 4WD

Auto Trans

4.3l vortec.

 

Had some issues over the last few days that have ultimatley ended in misfires.

 

Had it hooked up and the report said a bad O2 sensor, random misfires in cyl 1 3 and 5 and a heater circuit problem. The misfires are my concern here. Any ideas as to what would cause one side of the engine to get so many misfires? It happens when idling, driving and at stop lights.... Pretty much steady. It's all on the drivers side. I'm in Ontario Canada.

[DofD]

I'd get your distributor and plug wires checked/changed to start with. The O2 sensor probably needs replacing as well.

[Draenor]

One correct the O2 problem.

Two, How many miles?

Three, When is the last time you have done a tune up?

[MikeInCtown]

Hey everyone.

 

Truck in question:

1999 GMC Jimmy SLT

4DR 4WD

Auto Trans

4.3l vortec.

 

Had some issues over the last few days that have ultimatley ended in misfires.

 

Had it hooked up and the report said a bad O2 sensor, random misfires in cyl 1 3 and 5 and a heater circuit problem. The misfires are my concern here. Any ideas as to what would cause one side of the engine to get so many misfires? It happens when idling, driving and at stop lights.... Pretty much steady. It's all on the drivers side. I'm in Ontario Canada.

 

Check wires plugs and dist cap but it's likely none of those are the problem. Wondering myself if an intake gasket has failed. Check the oil and also coolant level.

[superjim]

Hey everyone.

 

Truck in question:

1999 GMC Jimmy SLT

4DR 4WD

Auto Trans

4.3l vortec.

 

Had some issues over the last few days that have ultimatley ended in misfires.

 

Had it hooked up and the report said a bad O2 sensor, random misfires in cyl 1 3 and 5 and a heater circuit problem. The misfires are my concern here. Any ideas as to what would cause one side of the engine to get so many misfires? It happens when idling, driving and at stop lights.... Pretty much steady. It's all on the drivers side. I'm in Ontario Canada.

 

 

 

What were the OTHER ISSUES that you had?

Check the wiring going to the O2 sensor first.

The heater circuit error relates to to the O2 sensor.

If wiring is all OK...Replace the O2 sensor.

 

What all have you did to it lately, that may relate to this one side of the engine?

Did you have the plug wires OFF?

Have you pulled the plugs to check their condition?

 

If the wires are old and have been disturbed, and are now running parallel and maybe touching each other, you may be getting dome inductance firing thru them.

Not too likely but it is entirely possible.

 

Give us more details.