History: https://poal.co/s/Cars/703234 So the Buick I have been fighting seemed fixed and worked for a bit, then the random shutting off returned and with a vengeance. I could not go even a brief drive down the road without it shutting off, but now the transmission started to blow out. It would no longer move out of 1st, even manually setting to another gear, but it would reverse and neutral. I had already long suspected that when we got it replaced about 6 years back, they put in the wrong model as there is one specifically for the supercharged engine. Anyways, took it to the mechanic and we decided to move forward with a replacement. Fucking expensive. We mad the choice since the engine seemed to be in great shape, with exception to it shutting off, but when it ran, it ran great and sounded nice. So, the transmission was replaced and now we have severe knocking in the valve cover area. So we took it back as it wasn't there prior and the mechanic agreed to have a look. A few days later and they call me down to show me that there is no oil pressure bringing oil to the rockers/lifters (whatever they're called) and thus the knocking in the valve cover area. I explained that was not an issue prior; he explained they performed an oil change, main bearing seal change, the transmission itself, and replaced a MAP sensor as it apparently had issues as well (the one sensor I didn't replace). He claimed they couldn't really agree with noise being present prior since the car wasn't really running great and so it already sounded bad. I agreed as I am not trying to get money or free shit here, but the lifter noise was most definitely not there. In fact, I actually have video of the engine prior to trans change as a coincidence, but whatever. The mechanic has told me the engine needs rebuilt as this is likely bearing wear that has caused the oil pressure to not be where it should be, a legit diagnosis. HOWEVER - wouldn't this be present prior in many ways like low oil pressure lights and all sorts of issues to lead to an eventual pressure failure? This became an 'overnight' issue which doesn't sit well with me, though I am amateur at best. Anyways, they still have the car and agreed to pull the oil pan, check the screen and replace the oil with 10W instead of 5W (as per oem) and let me know. That was 5 days ago. Reading online, there are a few things that this can be; oil pump (though highly unlikely), sending unit/sensor, bearing wear, wrong oil type or filter, a leaking or misplaced seal,... There's quite a lot. Suggestions? Time to drive it off the local cliff?