Strange engine problem

[Sunfirecody]

I have a 1998 Pontiac sunfire convertible with the 2.4L engine and the automatic 5speed transmission. The car has a misfire condition I have done almost aleverything too atemp to fix her. Here is a lost of parts replaces in the last week.

MAF
IAC
ICM
Coils
Spark plugs and boots
Fuel pressure regulator
Fuel injectors (made it a little better) but now has a random multaple miss it olny had a cylnder 1 miss before.
Intake gasket
Vacuum hoses all were replaced.
Cleaned throttle body.
Air filter.
New batterie.

That's all I have done for now but when I replaced the injectors I olny replaces the cylinder one injector after the replace it didn't stumble as much the engine would shake before I replaced it and it had calmed it down but it still misses.
I have had the codes read and One was a po507 sonthing too do with the o2 sensor detectedit was running rich or lean. And the other was just misfire code.
I don't know what else too point twords becides fuel pump or the whole set of fuel injectors are cloged on the other two that weren't Replaced. Or the fuel filter s clogged giving bad pressure.

Have any ideas?
Any help is apreacated. Thanks

 

[tatey2457]

I think a bad O2 sensor making it run too rich could cause a misfire code but not sure if it'd just miss on one cylinder.

 

[Sunfirecody]

I don't think the sensor is bad but I forgot to say it's the rear bank sensor after the cat it just detects that it is running lean or rich but I don't remember. I'll re run the code in a bout a half hour.

 

[CatSkinner]

With all that you've done, if the O2 sensor doesn't fix the issue, you might want to consider checking compression.

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[Zimgxp]

The post cat 02 sensor just monitors the cat performance. It shows rich because it is missing. Did you replace the coil mouniting bracket aka the distributor cap? That code indicates that the idle is higher than programed into the computer. This coud ba a vacuum leak.

 

[CatSkinner]

Zimgxp's right about the code, P0507 isn't isn't an O2 sensor diagnostic (didn't pay attention before), do you have both a high rpm diagnostic and an O2 diagnostic?

 

[tatey2457]

A P0507 DTC trouble code may be caused by one or more of the following:

A vacuum leak
Leaking air intake after the throttle body
EGR valve leaking vacuum
A faulty positive crankcase ventilation (PCV) valve
Damaged/failed/dirty throttle body
Failed EVAP system
Failed IAC (idle air controller) or faulty IAC circuit