1985 2.8L automatic transmission
This car had an engine swap before I owned it, it may have been a FWD version.
With the brown wire unplugged and the timing set to 10 degrees BTC the engine idling about 800-100 RPM
The timing mark goes toward 0 degrees BTC up to about 2700 RPM
Then the timing jumps to about 23-25 degrees BTC and the RPM jumps to 3500-3700 RPM
With the brown wire hooked up the curve still appears to be the same.
This has stumped me I have poured over my manuals and the internet to no avail. Can anybody help me out?

 

There's NO way you have an FWD engine in the car as the mountings are completely different not only for the block but for the starter and other parts as well...

Your ignition module is bad if the timing is jumping... My first module, that was in the car when I bought it, wouldn't allow me to set the timing. I'd get the timing down close to 10* BTDC, with my hand on the dizzy (so it wasn't moving), and the timing would all of a sudden jump about 10 degrees (again, without the dizzy moving). Module was tested bad at AutoZone.

 

I had the Ingition module tested and it was good. I inspected the harmoonic balancer and the ring hasn't move in relation to the center. I noticed three wires going into the motor above the cam sprocket just behind the water pump adapter and in front of the LIM. Could this motor be a 3.1 or a 3.4 because I don't think the 2.8 in 1985 used this sensor.

 

That would be a 3.4, I believe, and the sensor at the front of the intake manifold is the cam position sensor. Should NOT be connected to anything, as no ECM GM used before about 1994 had any use for a CMP, which is how the ECM gets the signal for the sequential fuel injection (indicates when the engine is at #1 TDC).

How good is the black pipe that should be running from the back of the intake manifold, near the dizzy, to the IAC nipple on the throttle body? Inspect it for cracks, breaks, etc, and especially on the rubber ends that tend to deteriorate. Also check anywhere else for vacuum leaks and deteriorating hoses and lines and clean the IAC passages in the throttle body.

 

I think you right the engine is a 3.4 and the cam position sensor wire is just hanging. I set the timing to 10 degree BTDC with the brown bypass wire unpluged. I also noticed that the idle stop that rest against screw that sets the idle wasn't bent at 90 degrees I bent the bracket to about 90 degrees and and the idle is more tolerable. The question now is what is the engine supposed to idle at in drive and in park? Can anyone help?

 

Idle speed is set, with the drive wheels blocked and parking brake set and the engine idling in Drive and up to operating temperature (in closed loop operation), to 650-700 RPM. You will need to put a wire in the diagnostic connector in the 2 top right hand terminals and turn the key on for 30 seconds before disconnecting the idle speed control motor, turning the key off and pulling the wire out of the ALDL before starting the engine to set the idle speed (this sets the IAC to the closed position so the engine is running on only the air coming past the throttle plate instead of the IAC bypass air).

In park, when cold, the idle speed should be around 1200 RPM, with the ECM controlling the idle speed, and should automatically drop to around 800-900 RPM as the engine gets to operating temperature.

All of this information is on the underhood Vehicle Emissions Control Information label, which is generally attached to the underside of the hood near the hood latch loop in the F-body.

:edit: I'm going to correct some info I posted above... The CMP was introduced on the turbocharged Grand National in 1987, which DID have sequential fuel injection. However, this CMP was basically a distributor replacement as is seen in some current GM V8 trucks (TrailBlazer) and on a number of similar vehicles. I have one of these contraptions in the garage.