05 LX470, 220k miles, no CEL, stored or pending codes.
I have had this issue for about a year now. It is slowing getting worse. I have zero idea where to go next, so here I am.
The first symptoms started when accelerating from a stop sign, usually on an uphill bit of road. I would get about halfway through the intersection, then lose power momentarily. Power would be restored after a second or two, usually with a little kick, and I would be on my way. It never lasted long enough for me to figure out what was going on, and was usually a surprise. Again, extremely intermittent - usually only once per drive and not every drive. This would happen usually when warm (on my way home from work), and once or twice on a cold engine (a block or two from the house).
The current set of symptoms include the first, but those have become even less frequent. The more common presentation is on the interstate, at about 55mph and downshifting 5-4 (auto) when attempting to pass. As you push your foot more on the accelerator pedal, the truck will try to downshift from 5th to 4th. At this point, the revs will drop to idle (700 rpm ish). A second or two passes (feels like an eternity), and 4th gear will activate, usually slightly violently as your foot is now planted to the floor as a reaction to having no power with the freeway psychos behind you. This does not happen on every down shift; it is extremely unpredictable and seemingly random. It may be happening on other shifts and I have not detected it? No CEL or other dash lights.
Over the last year, I have replaced the following with new, OEM Toyota, except where noted:
Today I dropped the transmission pan and checked the resistance of the solenoids in the valve body. All are within spec. Fluid is a little dark, it was changed about 6 years / 50k miles ago. No obvious signs of issues in the pan. There is what I feel to be a reasonable amount of schmoo on the magnets. I will run the fluid through a paint filter later, but I don't expect to find anything of note. I was hoping to find a solenoid that was out of spec, and I'm a little disappointed I couldn't find a smoking gun. I also inspected the outside of the wiring harness for any potential rodent damage, but found nothing. I was unable to completely remove the harness from the truck for a more throrough inspection. Overall, the wiring harness and connectors look to be in very good condition.
I have found a few threads with possibly similar issues but nothing that has helped. I am at the end of my rope on this one. Thanks for any help you can offer.
I have had this issue for about a year now. It is slowing getting worse. I have zero idea where to go next, so here I am.
The first symptoms started when accelerating from a stop sign, usually on an uphill bit of road. I would get about halfway through the intersection, then lose power momentarily. Power would be restored after a second or two, usually with a little kick, and I would be on my way. It never lasted long enough for me to figure out what was going on, and was usually a surprise. Again, extremely intermittent - usually only once per drive and not every drive. This would happen usually when warm (on my way home from work), and once or twice on a cold engine (a block or two from the house).
The current set of symptoms include the first, but those have become even less frequent. The more common presentation is on the interstate, at about 55mph and downshifting 5-4 (auto) when attempting to pass. As you push your foot more on the accelerator pedal, the truck will try to downshift from 5th to 4th. At this point, the revs will drop to idle (700 rpm ish). A second or two passes (feels like an eternity), and 4th gear will activate, usually slightly violently as your foot is now planted to the floor as a reaction to having no power with the freeway psychos behind you. This does not happen on every down shift; it is extremely unpredictable and seemingly random. It may be happening on other shifts and I have not detected it? No CEL or other dash lights.
Over the last year, I have replaced the following with new, OEM Toyota, except where noted:
- Fuel Pump
- Fuel Pump Sock
- Fuel Filter
- Mass Air Flow Sensor - Hitachi
- Throttle Body
- Air Filter - Wix?
- Accelerator Pedal - used OEM
Today I dropped the transmission pan and checked the resistance of the solenoids in the valve body. All are within spec. Fluid is a little dark, it was changed about 6 years / 50k miles ago. No obvious signs of issues in the pan. There is what I feel to be a reasonable amount of schmoo on the magnets. I will run the fluid through a paint filter later, but I don't expect to find anything of note. I was hoping to find a solenoid that was out of spec, and I'm a little disappointed I couldn't find a smoking gun. I also inspected the outside of the wiring harness for any potential rodent damage, but found nothing. I was unable to completely remove the harness from the truck for a more throrough inspection. Overall, the wiring harness and connectors look to be in very good condition.
I have found a few threads with possibly similar issues but nothing that has helped. I am at the end of my rope on this one. Thanks for any help you can offer.
