Hello to all I have a 1993 Camaro Z28 with 5.7 auto trans , I have replaced plugs , wires , optispark, O2 sensors , fuel pressure regulator, EGR valve, coil, TPS and MAP sensor, the engine is running rich and I can't find a vacuum leak ? The old plugs and O2 sensor were coated in black soot.
I have read about the intake gaskets failing could this be a source of incoming air ?

 

Seems like the extra air should make it run lean rather than rich. Have you looked at the O2 sensors with a scanner to make sure they are actually working? May also want to look for injectors leaking or sticking open, and check the fuel pressure.

 

The reason I suspect air in leakage is all 8 plugs and both O2 sensors were fouled. I only have 2 O2 sensors one on each exhaust manifold and no MAF sensor the MAP sets fuel flow with correction from TPS and O2 sensors. The TPS tested within specs and the O2 sensors are new. I do not have a reader to analize the data provided. It sounds like a vacuum leak on the back of the intake manifold and there is oil dripping down the passenger side rear of the intake.

 

the great unknown about used vehicles is that we don't know what the prior owner did. Has the vehicle done this since you've owned it or did you just discover this when doing preventive work and it probably has been that way?

there is always a chance that the prior owner has a non stock tune running

the oil leak needs to be fixed

a cheap way to see if the car runs less rich is slap on a cheap ebay CAI. See if making the air flow more freely helps.

Since putting headers on my 95 4th gen I replace O2's every year or else live with 4-5 mpg less.

 

I know this is an obvious one, but did you check to see that your air cleaner element is "clean"?
A restricted air cleaner restricts air flow, which can mean a richer running engine.

 

woh,,, you have a bunch of good used sensors. test the evap system. number 8 here https://camaroforums.com/forum/93-02...62/#post557634 i would change intake gaskets, rear and front seals on the intake are rvt and **** to fail. then while doing that you can replace the injector o rings and maybe get the injectors cleaned and flow tested. pull the ecm and see if it has a aftermarket chip in there.
this is a prom (blue and brown) with a chip (green) hooked to it.



ecm, prom is under the grey cover

 

Not if you're talking about the end valley gaskets, where you say it's leaking oil.
Those have to do with crankcase ventilation, but would have no effect on your air/fuel mix or making the engine run rich.

 

wont know if the intake gasket/s is failing until its apart. mine was leaking but the gaskets were hard and bolts where not tight at all. it was so bad i was getting oil in the head intake passages along with the air. i also had two injectors that were not flowing well which can cause a rich condition.

 

Thanks to all for the information and direction. A little history on the car I purchased it from the previous owner who had lost patience with it and decided to sell it. I had some sweet cars when I was younger , with my kids grown and off doing their thing I picked it up for a project and it has turned out to be that and more. If it were carbed and older I'd have ton of confidence in my knowledge. I like to learn so I decided to dive in, this website and its members make it possible.
I replaced the sensors due to a code 22 TPS the others without knowing when they were replaced if at all will be 20 years old next year. The old O2 sensors were plugged with soot and the intake was full of soot as well. I am cleaning out the intake and throttle body. It looks like one or more of the injectors were sticking open and causing a very rich condition.
Ill pull the pcm tomorrow and check the eprom.

Thanks to everyone who provided help and when its running and cleaned I'll post some photos.
I am going to repalce the intake and exhaust gaskets this week , the injectors are being tested and cleaned at a locla shop and should be back next week as well

 

doesnt take long to do the injectors. had mine back in 3 days and thats with the 2 days shipping to/from olympia. there is no comparison to the old carb'd motor and the lt1, your gona like it allot