I am the second owner of a 2001 DeVille DHS, the first owner being a late member of the family and had bought the car outright from the dealership brand new. She was meticulous in it's upkeep and had the money to support that. I have a file folder containing every service or maintenance record of the car's life, right down to every oil change and tire rotation ever done. It has 160,000 on it and essentially the previous owner drove it to church and back and that is about it. She lived in Portland, OR.
At the 40,000 mile mark, the transmission was rebuilt entirely. I'm not able to determine why but nevertheless, 11 years into it's life it had some sort of transmission failure. But again, the transmission fluid has been consistently maintained.
When I received the car as a gift it ran well for a few months and then started acting up. The following symptoms are sequencial:
-Car was running and parked. I tried to turn the key to turn it off but key was completely stuck in the ignition cylinder and the dash lights had completely shut off. I could not turn the car off and could not recover the dash lights but would still engage in gear and drive fine. I had to pull the fuel pump fuse in order to get the car to shut off. Replaced the ignition cylinder.
-Right after the ignition cylinder was replaced, I drove the car a day and the service engine light came on and started blinking. I researched the reason the light would blink instructed me that the issue was severe and that I shouldn't drive the car any more until it was fixed. The code thrown was a p0303, a cylinder 3 misfire. I detailed the rear bank pistons and replaced the valve cover gaskets.
-Turned the car on and the engine started vibrating in a way. It was jerking a little when turned on and while at idle the engine would fluctuate revving, increasing RPMs between 1500-2400, with a high pitch/low volume whining sound coming from the left side of the engine bay. Only did that the once and hasn't since.
-Attempted to complete a long drive, about 4.5 hours but at the 4 hour mark I got off the freeway, drove through town at 25mph and randomly lost almost all acceleration and the transmission shifted to 1 and wouldn't go any higher. I pulled to the side and turned it off/on, rand codes (40 codes were found so I considered that implausible), checked fluids and such, added some oil, still didn't have reverse but I could engage in drive and I attempted to take off. Still wouldn't shift out of 1st and the whining sound continued. I pulled over again and disconnected the battery for 15 mins. Reconnected and took off, car acted completely normal. I got onto the freeway and was doing 80mph for about 5 mins until I lost all gears again and coasted to a safer resting spot. 30 miles away from my destination and I had to tow it the rest of the way.
Current Symptoms:
-CEL still P0303 (cylinder 3 misfire)
-Won't engage in reverse
-Operates when driving for approximately 3 miles but won't shift out of what seems to be limp mode, and the whining increases with acceleration.
-After about 3 miles, acceleration ability decreases until I can only push her to go about 8mph max. I can pull over and disconnect the battery and after that it runs like "normal" again for another 2.5/3 miles and then acceleration is gone again.
-Engine still vibrates/shakes
What I Have Replaced:
-Ignition cylinder
-Valve cover gaskets
-Spark plugs
-Rear coil pack
-MAF
I can't figure out what is still wrong with it! Why is it stuck in limp mode? Where is the whining come from? Why does it almost entirely lose acceleration at a certain point and when I disconnect the battery for a brief second it resets itself back into regular limp mode? Why can't I engage in reverse?
Please help!
Thursday, October 16th, 2025 AT 2:13 AM
