Ok so as you guys know i have replaced endless parts on this car and everyday something new pops up. The Low Oil Pressure light has been on for the past week, it only comes on when im at an idle so i have ruled it to be the Sending Unit. I have to find some time to replace it still. Then today on my way to school after about 35 minutes of driving im sitting at a stop light just playing some music and then all of a sudden the car sputtered and then died. I started it back up reved it a bit let it idle again and then it died once more. Started it up again held it at about 2500 RPM until the light turned greened then i just went to my school down the road and parked it. I had it idling at school and it never died, even with the bass pumping. I checked my battery and alternator and they are both working perfectly so i can rule those out. I was thinking it was my IAC but i cleaned that 5000 km's ago when i did my intake gaskets, anyone have an idea why that happened? On my way home it didnt die once. Also i checked the oil and i was down about 3/4 of litre. Is that normal for the engine? Last time i did the oil change was a bit over 5000 km's ago using 5w-30 Synthetic.

 

Darn metric units.

Just because you cleaned the IAC doesn't make it infallible. I would call it a fluke for right now, but if it happens again, just unplug the MAF sensor and try to start the car and drive. That's a good way to rule out that sensor.

I'm going to say that that is NOT normal loss for the engine. You might have a leak, check around the valve covers and the oil pan gasket.

 

I know you had a thread about the low pressure issue. I'm not sure what was done to come to the conclusion it's the sending unit, but in the world of hypotheticals, say it's not the sending unit. If you are losing oil and having low pressure, you could be causing your engine serious harm, hence the stall. Oil starvation can lead to possible engine seizing.

Now, if it's not oil related, I believe Chibi hit the nail on the head. Failing MAFs do screwy things. Unplugging the MAF is the quick and easy way to try and figure out if that is what's causing the issue.

 

If you're going to test the MAF start by testing the circuit first. Unplugging the MAF will not tell you if you have a loose/dirty connection. It will only force the PCM into open loop and it will pull fuel tables from memory instead of adjusting them in real time via sensors. This will richen up the mixture and can 'mask' other problems that may actually be the cause. Considering your problem is intermittent that in itself would make me suspect a bad connection. Sure, the car might run a little better with the MAF unplugged, but that doesn't mean the MAF is bad.

Part 1 -MAF Sensor Test (P0101, P0102, P0103): GM 3.8L (1996-2005).

If no problems with the MAF or the circuit are found then take the car to a shop that can monitor operation in real time with a scanner. That is the only way you are going to find out exactly what is going on at the time the engine sputters and dies. In the long run it will be less expensive to have it diagnosed compared to all the $$$ you're tossing at parts in hopes that it solves the problem.

And no, using that much oil in approx. 3100 miles is not normal.

 

I have been driving the car like this for the past week and a half. It it really had low oil pressure it would have died about a week ago. There is no valve ticking or major loss in power or fuel economy and it runs great. Ive been reading that bad oil senders can leak oil when they go bad? I check the oil about a month ago and i recall that it was at the full mark from doing the first oil change back in november.

 

No neccisarily. These is a difference between low/not enough oil pressure and NO oil pressure. Problems resulting form incorrect oil pressure may not be "instant" and may not give you symptoms (like ticking) now, but it could cause premature wear on various parts. Keep in mind, if I recall you stated that you oil pressure read fine, except when you are at a stop and at idle (which is not the most demanding stress on the engine, so the need for oil is less then when you are at high RPMs, but if you are truly getting NO oil during that time, the engine is running on the residue that is on those parts, it would take prolonged lack of oil to cause more immediate symptoms).
It's like blown LIM gaskets shooting coolant into your oil, sure the car may run fine and tended to quickly no longer term damage, or you keep driving, notice no issues and then one day you screw up a rod bearing due to coolant removing the oil that keeps it lubricated.

Most of the time, yeah they do. I've changed a couple myself that were infact leaking oil (one was real bad) right out the connector. I've also seen a failed oil pressure sending unit/switch throw a CEL code.

From what I understand, you have no code but a possible observation based on a gauge reading on your dash of the problem. Unless you diagnose (such as a mechanical gauge) or replace the the sending unit (to see if the gauge reading improves), you are riding on an assumption.

Not sure I follow this statement. Has the oil been changed since last November? I know these cars have an oil life monitor (which one can say I'm a little old school, but I still like to monitor the mileage, on conventional I go 3000-5000 miles between changes, that normally is about 3+ months). But if you have not changed the oil since November, we're about 6 months from November. Unless you don't drive your Monte very often, then you are probably over due for an oil and filter change.

I need to get this off my chest, I feel like I'm coming off as a jerk and I certianly don't mean to. I agree that in theory, your oil loss and oil pressure readings may very well be related to a failed switch/sending unit. But now your problem increased to a couple random shut downs. I have known of failing MAF sensors to cause the engine to just stall out of no where. You can sorta cheat and disconnect the MAF to see if the shut down goes away, but it's intermittant. Again, from what I understand, you have no CEL (granted, with the right ODB-II scan tool, if the stall was a result of a code, you still might be able to get information from the computer about what happened).

Your asking for insight and clearly explained you are losing oil and notice an issue of low pressure, now you have an additional problem that the car stalled out a couple of time. I'm just stressing until you have confirmed the source of the oil leak and/or confirmed your oil pressure situation, this still could be related to your engine stalling. And there is a chance, I'm completely wrong and it's something else, but when I'm tracing down a problem, I do what I can to diagnosis the issue. If I see possible related events, I try to see if they might be playing a part in big picture.

Again, please don't think I'm a jerk, I'm just trying to offer advice. At this point, I have offered all I think I can. I'll just wait to read your updates and see how things play out (each situation is a learning experience).

 

Haha i dont think your a jerk at all! Im just ruling out any internal engine problems due too that if indeed i had low oil pressure the engine would have seized by now. My Mechanic, Boss, and Teachers who have been mechanics for close to 30 years have all said if i had true low oil pressure that the engine would have siezed within the first day or so. Its been a week and a bit and engine still purrs like a kitten. Also about the oil i checked again and put it in december before christmas. I gone over 5000 kms but im running synthetic 5w-30 and the light hasnt come on yet but i will probably change it soon. Im saying that last month my engine oil level was perfect. My friends were suggesting i was burning it but if i was i would have lost alot more when i last checked it . With a bad oil pressure sender unit they say they can leak externally so thats were my oil leak could be from, i still have to find time to check so when i do ill let you all know.