Hello and thank you for taking time to answer my question. I will provide as many details as I possibly can. I’m by no means an expert, but I have probably 100 hours in this car working on repairing it. It was my uncles car, and he very much neglected it, only reason I bought it was because it’s technically the car I learned to drive a stick on, but also because I remembered it being rather fun to drive. I have a topdon obd scanner I’m beta testing, and I will include a log on engine pending and current codes if this form will allow me too. So a backstory of everything mechanical that I’ve done to this car. I have changed the oil twice, it has had many additives cycled through it to help possibly repair any damage (oil dipstick barely read any oil when I started working on it), I’ve changed transmission fluid, differential fluid, brake fluid with new brake pads and one rotor and caliper that Locked up, power steering fluid and a leaking hose, clutch fluid, I’ve changed the front differential mount bushing as it was shot, I have changed the driveshaft carrier bushing as well as the front flex disc because it was so worn you could not see any rubber left on it, I’ve changed a few airbags from a minor collision with the front detonator sensors and a bumper cover. Oh and I changed the factory original except for one (number 5 cylinder) spark plugs, all the coils and injectors as well as a new intake manifold gasket and the cars computer too. Quick story on number 5, it was the only one accessible without dismantling the manifold to access the others, someone stripped the new plug as I think it was the wrong threads, and so I drilled and tapped it used a helicoil and boom, good as new! I used all ruthenium Ngk plugs, Bosch coils, and I think just the standard ACDELCO injectors. I realize I have forgotten to give you the vehicle information, it is a 2006 Cadillac CTS base model with the 3.6L V6 engine in it with approximately 183,000 miles. Original motor and transmission. Now onto the problems I’m experiencing, I intermittently get a flashing CEL, and when pulling about 2500 RPM in 1st-3rd sometimes even 4th, I get this loud noise, sounds like bearing noises almost, coming towards the right side from what I hear. I’ve verified in neutral, this noise doesn’t exist, just sounds like normal engine noise. Now when I’m doing 75-80 and I let off the acceleration to maintain speed, there is a sweet spot where all that happens is jerking feeling, loud noise, and just very rough overall. Now my solution to this was to accelerate and maintain 80, I don’t like doing this because the speed limit is supposed to be 70 though nobody follows it. Usually if I drop to 70, it’s fine too though it can also be problematic. To me, when I’m accelerating from 0, when I hit second gear, the car gets really jerky, especially when I hit that 2.5-3k rpm mark, I can push in the clutch and then it like jerks almost, I can put it into 3rd gear, and then it’s almost like normal until it tops out in that mentioned rpm range again. My main question is if this is a transmission or engine issue? Something else that happened too, I filled up with Shell gas on my way home from work one day, my car sat in the driveway for a week while I worked on the radio, I tried to crank it and all it would do was turn but no fire, it finally would every now and then fire and hit about 1,000 rpm, I was finally able to finagle my footing to hold the clutch in, and hit the gas pedal when it fired and it took off after that, I held it at 2k until it warmed up and it idles just fine. I experienced a few misfires at highway speeds after that, used a fuel cleaner and it seemed good. I filled up with a mapco gas, ran that tank no issues, used marathon gas this most recent tank and now my issues are back, but almost in a worse way! It’ll crank, but the issues are the jerking and odd noises. I have brought it into a mechanic that I trusted, and this was when I used the Mapco gas I wasn’t having these major issues, but I thought the clutch and or transmission felt weird and so he told me that it drive normally for a RWD car, he didn’t find any issues on his shakedown, they balanced the tires and charged me $400. So needless to say I’m not all that happy, but not much you can do besides not go back there. Another thing I’ve had to do is run two wires and a momentary push button to bypass the cars starter relay. I’ve changed the clutch switch twice and the car wouldn’t recognize that the pedal was pushed in. Funnily enough the clutch sensor has two circuits, one for starting and other for cruise, the cruise portion works just fine, I’m able to see it change states on my semi fancy scan tool. When I first changed rhe ECM, the intermittent starting issue went away, but about a month after, the issue became not starting at all, so I was using a power probe and removing the starter relay and applying voltage straight to the starter solenoid, essentially exactly what I’m doing now, just with a convenient pushbutton located under my key. If the scan data will post, you can see the pending codes and I halfway wonder if my ECM is bad again? It only came with a 6 month warranty which of course is over now as I bought it in February or March I believe. Before changing the ECM, I had active misfires, but that was also when I changed the plugs coils and injectors, I changed the ECM maybe 15 minutes after changing the coils plugs and injectors, and it almost immediately ran better, it had to relearn its idle and stuff I think, but after a few minutes it was running smooth! I think I’ve provided as many details that I can, but if you need more details, information, or specific scans/codes, just let me know and I’ll see what I can do. I just really don’t want to bring it to someone and ring up a multi thousand dollar bill or something crazy. I bought the car for $650 as it had a salvage title and needed repairs, and all in all, I’m at a total of $7k now, and I don’t want to waste money, albeit some of those repairs were tires and other necessary repairs regardless of car’s condition. I also realize that is I try to sell this car now, I will definitely loose money. My plan was to drive this to work and back (80ish miles round trip) to avoid the wear and tear on my really nice truck, and I was going to drive this until the wheels fell off. When I was running the Mapco gas I could get 28 on the interstate and about 24 combined mileage. Now, I’m not sure what it is as I haven’t looked, but I imagine it’s pretty bad with how rough it’s running.Pending Codes Active Codes

I had to add permalinks to a Google drive document, if you click those you’ll be able to view and or comment on my uploaded pdf containing the active and pending codes (2 different documents and links).