Hi, my car has been misfiring and running super lean.

I cleaned the spark plugs, and changed the wire.

It seems that it's an air/fuel issue, but I don't know where to start where to start checking what the issue is...

EDIT:: btw, there was more exhaust than normal coming out of the tailpipe

I'm losing my mind. Any suggestions?

If you need more info, let me know

 

More exhaust or more visible moisture vapor?

Check for exhaust system leaks.

 

To be honest, it seems like moisture because it is really colorless, or even like a light gray. There is a pretty strong gas (?) smell

My spark plugs are black, so I guess that's from excess carbon from the air intake?

 

Perhaps the exhaust output is the same but the fuel/air ratio is now rich.

Is the cars check engine light on?

Does the engine NOT misfire at certain times such when first started cold?

How does the engine idle (hot/cold), smooth, rough, etc.

The check engine system should in theory trigger if the components monitored are not working up to speed but it is not 100%

Common issues for too rich are bad O2 sensor or engine coolant temp sensor (ECT) which monitors coolant temp for engine computer.

Lower on the list are leaking fuel injector, fuel pressure regulator, extremely poor ign spark, MAJOR clogged air filter - not just dirty.

Ask around if you know someone with an ODBII code reader having real time data output. The code reader can output real time sensor info from those items the check system monitors and may be of help narrowing down the problem. Plus readout any pending codes, these being codes still awaiting final disposition from repeated test cycles and as such the check light has not been triggered.

Not all systems are monitored.

 

It misfires when I'm driving, and idles really rough.

I sprayed brake cleaner to find a vacuum leak, and didn't hear any difference.

Would a bad o2 sensor cause misfiring?

 

A bad O2 sensor could cause these issues.

Suggest before replacing parts to have someone use an ODBII reader to output real time data and if present pending trouble codes. A bad O2 sensor would show up by its signal output which the code reader will be able to monitor.

Could also be poor ign spark, leaking injector.

Note: Don't drive too much until you fix the problem. Excess fuel in the exhaust results in high temps inside the emissions converter which will wreck the converter.

 

don't forget... you can get your cars codes read at an Autozone