My 04 Toyota sienna is having a bunch of weird issues that I can't even begin to diagnose. Everything except the check engine started yesterday, the check engine started about a month ago.
Circumstances: 170k miles, VERY cold today 12-15 farenheit. I barely warmed up the car before driving.
1. Turning the wheel while backing out of my driveway was much more difficult than normal. I wondered if there were any issue with the power steering.
2. I swerved the car left and right to check steering while going about 15-20 MPH. At that point the brake light and tire pressure lights turned on. When I drove straight again they turned off.
3. When accelerating to passing speed, either from a stop or while moving, the car didn't immediately accelerate. The engine revved as if it was in neutral for a half second or so, then the car accelerated in a burst.
4. The radio was randomly losing power.
5. While driving over 40 MPH, the speedometer was dropping and then jumping back up. It would go from about 45-15 then back up in quick regular jumps. These jumps would happen every 3-4 seconds. While this was happening the check engine light would occasionally blink, but was not flashing steadily. During this time nearly every warning light was on: ABS, CHECK ENGINE, TRAC OFF, TIRE PRESSURE, vsc, little car with squiggly lines, brake.
6. I turned on the heater onto the auto setting (automatically adjusts air temp and blower speed to hit desired temp). It turned on full blast but then shut off a second later. The panel still showed it was on and going full blast with the correct temp but the fan had shut off. A few seconds later it turned on again.
Today, I drove it to Autozone to have them pull the codes and it drove fine on the way there, only the check engine light was on. The pulled codes and the only code that came up was P0430. I turned right out of the parking lot and all the same stuff started happening again. I turned around to see if they could re-pull the codes now that it was happening again and the car went back to driving normal. I drove around for a bit to see if I could get it to happen again and when I hit a bump while making a right hand turn, it happened again, this time I felt the car misfire as well.
Here is a brief video I was able to take while it was happening yesterday:
https://www.youtube.com/watch?v=ate2jeuewSgI'm happy to provide any other info or attempt any other diagnostics/tests.