Where to begin? I have some really weird things going on. First, let me list major mods because, perhaps it may help someone pin point what the hell is going on with this car. It is a 2002 Camaro SS, M6, with 60K miles. Stock block, MS4 cam, Patriot II heads, LTs, etcetera. Under drive pulley, electric water pump, ported oil pump, new alternator, ported Stock Throttle body, speed density tuned, deleted MAF and rear O2s, ls6 valley cover conversion. 19x11 in rear, 18x10.5 in front, 3.90 gears, of which were never tuned for.

It started with a low oil light. I change the oil sensor, light still on, even with fresh oil topped up and about 400 miles after the oil change, light still on. Next, I noticed my cruise control rarely works and the ASR light comes and goes, ABS also goes inop at 80+mph, all of which are probably due to the PCM getting confused from the wheels and gears.
So now the car stalls when breaking and seems to do so even faster with the A/C on. Tonight I noticed a loud squeaking noise coming from the front top of the engine somewhere. It goes away at idle but gets louder with throttle. It doesn't appear to be a loose belt issue. I am dumbfounded as to why the car is all of a sudden stalling at breaking and sometimes tries to at idle. the voltage gauge spikes from 6-12 volts randomly. Also, what is causing the squeezing noise? It almost sounds like it is coming from the throttle body, maybe even under a valve cover, but sounds closer to the throttle body.

Sunday I will run EFILive to see what codes I am getting.
Can anyone chime in? I am now a retired military guy with a small business. I have to pin point these issues and get them fixed. I use this car daily.

Thanks in advance!

 

I can't answer to your ABS stuff, but the stumbling/stalling thing at idle - and worse with AC on combined with that high pitch noise sounds very much like a vacuum leak. While you're getting it looked at with EFI Live, spray WD40 around the intake manifold while your tuner watches the O2 / fuel trim data. When you hit a spot with WD40 that changes your fuel trims, you found the leak. Don't rule out the MAP sensor at the rear of the intake manifold. That's a common leak also

 

The oil light and voltage gauge sounds like a possible dash grounding or shorting issue. I've had to chase those down before and they suck.

 

Tune the car for the gears. Your car is reading sensor values that are not in range for your old rear end. Fix that and you should fix a few of those issues.

A basic tuner for your car should be able to adjust it correctly.