3.8 ltr pontiac - gas in oil,no detectable vacuum leaks, runs smo

If the check engine lite is on, check for applicable trouble codes. Around here some of the national brand autostores will check some codes for free. How long since a tune-up?
The basics for a rough idle, is to check for a leak of some kind, fuel--egr--vacuum, something of that nature.
If a temp issue, check coolant temp sensor.
I don't know year--make--model?

The only thing I can think of is the vacuum leak in the back of your motor next to the firewall there's a main vacuum it operates all the vacuum check that little 90° angle hose that goes into your manifold.

P0102 - The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load situation. The MAF sensor has an ignition 1 voltage circuit, a ground circuit, and a signal circuit. The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency will vary within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. DTC P0102 will set if the PCM detects a frequency signal lower than the possible range of a normally operating MAF sensor.
Sounds like you need a mass air flow sensor , but take it to a ASE certified repair shop an have it check , instead of just replacing it.
DTC P1189
The engine oil pressure switch is a normally closed switch that opens with the proper oil pressure. With the ignition switch turned ON and the engine not running, the PCM should detect a low signal voltage input. With the engine running, the pressure switch opens, and the PCM should detect a high signal voltage input. The PCM tests the state of the engine oil pressure circuit with the ignition switch turned ON, and the engine turned OFF. If the PCM detects a high voltage input on the engine oil pressure signal circuit, DTC P1189 will set.

Sounds

I am chasing this problem also in my 94 Camry. I am investigating

- vacuum leak somewhere in the intake manifolding or hose
- EGR valve malfunction
- IAC valve malfunction
- deteriorated spark plug leads
- head gasket leak
- fuel pressure low from pump
- malfunctioning fuel pressure return or relief valve

if the coolant level is going down you may have an intake or head gasket leaking coolant into the cylinders pressure test the coolant system

Let me start by explaining what trouble codes are.
Codes are only a guide for mechanics to use to troubleshoot problems. They are never a directive to replace parts.
Code 442 means the computer has detected a small leak in the system that vents fumes from the gas tank to the vapor canister. The system would need to be checked out to find that leak. It could be the gas cap or several other components.
Code 128 means the engine is not reaching normal operating temp. The most common cause is a faulty thermostat.

CODE 11 No distributor referene signal detected during engine cranking....Check circuit between the distributer and the pcm.

CODE 12 Problem with battery connection.Direct battery input to pcm disconnected within the last 50 ignition key-on cycles.

CODE 13** Indicates a problem with map sensor vacuum system.

CODE 14** map sensor voltage to high or to low.

CODE 15** Problem with vehicle speed sensor signal.No vss signal detected during road load conditions.

CODE 17 Engine is cold to long.Engine coolant temp stays below normal operating temp(check thermostat).

CODE 21** Problem with oxygen sensor signal circuit.Sensor voltage to computer not fluctuating.

CODE 22** Coolant sensor voltage to high or to low.Test coolant temp sensor.

CODE 23** Indicates that the air temp sensor input is below the minimum acceptable voltage or sensor input is above the acceptable voltage.

CODE 24** Throttle position sensor voltage to high or low.Test the tps.

CODE 25** Idle air control (IAC) valve circuits.A shorted condition is detected in one or more of the IAC valve circuits.Or a vacuum leak has been detected.

CODE 27 One of the injector control circuit output drivers does not respond properly to the control signal.Check the circuits.

CODE 31** Problem with canister purge solenoid circuit.

CODE 32** An open or shorted condition detected in the EGR solenoid circuit.Possible air/fuel ratio imbalance not detected during diagnosis.

CODE 33 Air conditioning clutch relay circuit.An open or shorted condition in the compressor clutch relay circuit.

CODE 34 Open or shorted condition in the speed control vacuum or vent solenoid circuits.

CODE 35 Open or shorted condition detected in the radiator fan low speed relay circuit.

CODE 37** Open or shorted condition detected in the torque converter part throttle unlock solenoid control circuit.

CODE 41** Problem with charging system.An open or shorted condition detected in the generator Field control circuit.

CODE 42 Fuel pump relay or auto shutdown relay (ASD) control circuit indicates an open or shorted condition.

CODE 43** Multiple cylinder misfire detected.Peak primary circuit current not achieved with the maximum dwell time.

CODE 44 Battery temperature sensor volts malfunction.Problem with the battery temperature voltage circuit in the pcm.

CODE 46** Charging system volts to high>Computer indicates that the battery voltage is not properly regulated.

CODE 47** Charging system voltage to low.Battery voltage sense input below target charging voltage during engine operation and no significant change in voltage detected during active test or alternator output.

CODE 51** Oxygen sensor signal input indicates lean air/fuel ratio condition during operation.

CODE 52** Oxygen sensor signal input indicates rich air/fuel ratio during engine operation.

CODE 53** internal pcm failure detected.

CODE 54** No camshaft position sensor signal from distributer.Problem with the distributer synchronization circuit.

CODE 55 Completion of fault code display on check engine lamp.this is end of message code.

CODE 62 Unsuccessful attempt to update EMR mileage in the controller EEPROM.

CODE 63** Controller failure.EEPROM write denied.Check the PCM

sounds typical of when these early injectors fail they just quit working after warm i would test the injectors resistance after reaching normal operating temp

Have you checked the fuel pressure regulator for leaks into the intake

sounds like the mass air flow sensor it is located on the air inlet try unplugging it and see if it runs better when it is running rough