Misfires on 99 chevy suburban

[patrickamp]

I have a 99 suburban driving me crazy..i have replaced the plugs, wires, rotors, distributor cap and spider injectors and yet
still getting misfires. My mechanic has said that the burb is throwing O2 codes and bad converter errors.

Several questions….can bad O2 sensors cause misfires
can bad convertors cause misfires
Can a combination of the 2 cause misfires

or
Do I have a bad ignition coil which hasn’t been replaced yet.

Also what is a good scan tool to purchase for an above average do it yourselfer.

Thanks in Advance for your help….Tired of incompetent mechanics.

Topic

[college man]

[quote=”patrick anderson” post=184439]I have a 99 suburban driving me crazy..i have replaced the plugs, wires, rotors, distributor cap and spider injectors and yet
still getting misfires. My mechanic has said that the burb is throwing O2 codes and bad converter errors.

Several questions….can bad O2 sensors cause misfires
can bad convertors cause misfires
Can a combination of the 2 cause misfires

or
Do I have a bad ignition coil which hasn’t been replaced yet.

Also what is a good scan tool to purchase for an above average do it yourselfer.

Thanks in Advance for your help….Tired of incompetent mechanics.[/quote]

If you can post any codes that you got that would help. An o2 sensor can cause misfires.
The o2 plays an important role in fuel delivery. Here is a video of how an o2 sensor works.

[Chris]

[quote=”patrick anderson” post=184439]I have a 99 suburban driving me crazy..i have replaced the plugs, wires, rotors, distributor cap and spider injectors and yet
still getting misfires. My mechanic has said that the burb is throwing O2 codes and bad converter errors.

Several questions….can bad O2 sensors cause misfires
can bad convertors cause misfires
Can a combination of the 2 cause misfires

or
Do I have a bad ignition coil which hasn’t been replaced yet.

Also what is a good scan tool to purchase for an above average do it yourselfer.

Thanks in Advance for your help….Tired of incompetent mechanics.[/quote]
O2 sensor or catalytic converter will not cause misfire but a clogged catalytic converter will cause your engine to get hot. Check the O2 sensor first make sure it is not malfunctioning. If it isn’t then look at the catalytic converter being changed. As for the misfire, I would suggest that the sparks are firing in the correct order. Look at the manual and it should tell you.

[patrickamp]

Sorry I don’t have any error codes at this time relying on my mechanic. I will when I talk to him.

My Converters rattle as well….so If I replace O2 sensors without replacing converters am I damaging anything
and……can I run with empty converters without problems as well.

I don’t live in an area where we have to worry about emissions and testing.

and lastly what type of scan tool would you recommend to a guy who is handy with tool willing to dig in and work.
I replaced my spider injectors last week so not afraid to try.

thanks in advance.
Patick

[Billy]

Any cheap scan tool from eBay or whatever will pull basic OBD2 codes, which may be sufficient in this case. Autel and Centech are well-known brands but by no means your only cheap options. Harbor Freight is also a good source.
For troubleshooting cats and O2 sensors, you may want to consider something with live data capability.
https://www.scantool.net

Get those codes before replacing anything.

[college man]

[quote=”ElCrazy93″ post=184450][quote=”patrick anderson” post=184439]I have a 99 suburban driving me crazy..i have replaced the plugs, wires, rotors, distributor cap and spider injectors and yet
still getting misfires. My mechanic has said that the burb is throwing O2 codes and bad converter errors.

Several questions….can bad O2 sensors cause misfires
can bad convertors cause misfires
Can a combination of the 2 cause misfires

or
Do I have a bad ignition coil which hasn’t been replaced yet.

Also what is a good scan tool to purchase for an above average do it yourselfer.

Thanks in Advance for your help….Tired of incompetent mechanics.[/quote]
O2 sensor or catalytic converter will not cause misfire but a clogged catalytic converter will cause your engine to get hot. Check the O2 sensor first make sure it is not malfunctioning. If it isn’t then look at the catalytic converter being changed. As for the misfire, I would suggest that the sparks are firing in the correct order. Look at the manual and it should tell you.[/quote]

Guess again on a bad o2 not causing a misfire.

[Chris]

[quote=”college man” post=184471][quote=”ElCrazy93″ post=184450][quote=”patrick anderson” post=184439]I have a 99 suburban driving me crazy..i have replaced the plugs, wires, rotors, distributor cap and spider injectors and yet
still getting misfires. My mechanic has said that the burb is throwing O2 codes and bad converter errors.

Several questions….can bad O2 sensors cause misfires
can bad convertors cause misfires
Can a combination of the 2 cause misfires

or
Do I have a bad ignition coil which hasn’t been replaced yet.

Also what is a good scan tool to purchase for an above average do it yourselfer.

Thanks in Advance for your help….Tired of incompetent mechanics.[/quote]
O2 sensor or catalytic converter will not cause misfire but a clogged catalytic converter will cause your engine to get hot. Check the O2 sensor first make sure it is not malfunctioning. If it isn’t then look at the catalytic converter being changed. As for the misfire, I would suggest that the sparks are firing in the correct order. Look at the manual and it should tell you.[/quote]

Guess again on a bad o2 not causing a misfire.[/quote]
On a 99 suburban? I thought they were strictly measurement tools in this model. It was my understanding, but please correct me if I am wrong, that if it lost something like that, it would throw the car into its “safe mode”. I don’t know the correct term for it. I know cars like a 97 civic HX or something similar they are very important. If they do cause misfires on this though then yes I would say look at those as well as firing order to make sure either one is working correctly. You did mention that you changed the injectors though. Usually when attempting to do upgrades like that, you want to get the computer re programmed unless they are OE spec. That may be part of the issue you are having. I would do research on them see what the manufacture recommends.

[patrickamp]

Eric;

Got those scan codes they are as follows:
PO133 O2 signal low bank 1 sensor1
PO171 Fuel system too lean Bank1
PO174 Fuel system too lean Bank2
PO430 Catalyst efficiency low bank2
PO452 Evap Pressure sensor signal low
CO281 stop lamp switch circuit open
CO226 LF wheel speed sensor no signal
any help would be appreciated.
Thank you in Advance

[Charles]

Is the fuel mileage low? Running too rich? With a PO171 and PO174 (both banks) and lower than 16MPG I would clean or replace the MAF sensor. Also could be a massive vacuum leak. If your scanner can monitor real-time metrics, check the fuel trims while running at idle and 3000 RPM to see if the fuel trims improve. Had the same issue and on the GM’s of that vintage its hard to test the MAF account it outputs a frequency instead of a voltage signal.

[Author]

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