Engine will run but rough with map vacuum disconnected.connect vacuum to map it leans out fuel and shuts engine down.

sounds like the pump is putting out the wrong pressure.

Check fuel pressure regulator for a rupture by pulling off the vacuum line and see if it is full of fuel.

Something odd about what you posted. An engine that is running lean shouldn't be using a lot of fuel. Lean is when there isn't enough fuel going into the engine. Two other sensors that regulate fuel flow are the map sensor and throttle position sensor. Temp sensor generally would cause a rich condition but I'd test that too. Be sure to check for vacuum leaks at the manifold and lines as well as fittings... A vacuum leak will give the O2 sensor a lean reading...seeing that, the computer will try to compensate by adding fuel. Clearing codes can change the way it's running but as soon as the computer runs through it's internal diagnostics it will turn the light back on if there is a problem.

DTC - 34 MAP Sensor Circuit Error (Signal Low Indicating High Vacuum)

The ECM uses the Manifold Absolute Pressure (MAP) sensor as an indication of engine load. High voltage would indicate low engine vacuum and higher engine load. Low voltage would indicate high engine vacuum and lower engine load. The ECM uses the information from this sensor to help calculate fuel delivery and spark timing.

Fault Code Description:
* 34 - MAP sensor circuit error (signal low indicating high vacuum)

Symptoms:
* Poor engine performance
* Engine running lean (not enough fuel, hard starting, lack of power)

Common Problems:
* GM MAP sensors do not commonly fail
* Due to erratic engine vacuum, other engine performance problems can cause a code 34 to set


Good luck (remember to rate this answer).

Check for vac leaks. Check all vac lines for cracks especially where they connect. (also power brake booster hose)

That is a map sensor code and a lean bank fuel code. I would suggest replacing the MAP Sensor but before you do that makes sure all the wiring connections to the sensor and wires themselves are in good shape. Also verify that the rubber hose connecting the sensor to the manifold is not split. The P0105 code sounds like the main code and the P0171 code sounds like it is a result of the first code. The MAP(Manifold Air Pressure) Sensor basically uses manifold vacuum to determine the amount of load on the engine and thus how much fuel needs to be added for proper operation. If any of the above described conditions are present it is very easy for the system to run lean. After repair use a scan tool to clear the codes and you should be good to go . I hope this helped you.

Lean code , lean condition is always an interesting problem to solve, if you found a vacuum leak your job is done, but if you didn't the fun begins,
First if you have an engine scanner you have to write down a o2 sensor voltage or short fuel trim value your job is to change those numbers if the fuel pump is weak the trim value would be negative -7 or less, and the O2 sensor voltage would be less than .45. Remember this part is important A good O2 sensor reads more or less .45, and short fuel trim 0 little less, little more. less than .30 or less than -5 would be a lean condition. items to check (test) Fuel Pump Pressure more that 35PSI,
Vacuum leaks including open PCV, Throttle tube for deformation and cracks, map sensor/or maf sensor that would give you a code, Bad fuel.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/flavio_517b938f50183b92

Code 51 = Oxygen sensor stuck in lean mixture mode. ( this will often cause engine to run rich due to oxygen sensor telling engine controller that it is running lean, thus send more fuel) This may be caused by M.A.P. sensor as well, so check vacuum lines and clean connections on MAP sensor first. It should be one of 2 things, Fault from MAP sensor, or faulty oxygen sensor.

12 is battery has been disconnected recently, or went dead.
51 is Oxygen sensor stuck on lean mixture reading
21- no change in oxygen sensor reading
53- internal problem with logic module
55- is end of message/codes.

51 & 21, basically telling you same thing, but I wouldn't jump at changing oxygen sensor first, as a bad M.A.P. sensor can cause a rich mixture, thus oxygen sensor switches to lean to try and compensate. Personally, I'd go with map sensor first, check connections and vacuum lines if all good, replace it, then I'd go to oxygen sensor .

vacuum leak in PVC line or clogged PVC. its a leak after the map sensor. o2 sensor is correcting for a lean condition so its adding fuel to your car when the o2 sensor detects the extra air.