Due to rough idle and error codes on my 98 LS400, I replaced the solenoids on the VVTi's on both banks. Bank 2 is fine, but Bank ! worked for less than a day after I cleared the codes then coughed up the same error code again (P1349), which it's been doing for years; and I bench tested the old one which seemed to opening and closing just fine. BTW I used units from NAPA. Anyone know the correct voltage range and if it is steady state or pulsating? Is this an all-on/all off-type switch, or does it open and close gradually in tune with engine rpm? Somewhere I read that these type only start to open at above 2000 rpm; if so, why does it seem to affect the idling? Does this seem like an ECM problem? Would there be any point in pulling the ECM connectors and checking for any visible signs of corrosion or bad connections? Anyone know which connector feeds the VVTi solenoid? The unit is 24 years old; do they wear out?

 

Have you checked the OCV filter?

 

if you have known good solenoids and clean OCV filters, check the wiring and connectors. they get crunchy with age and need to be replaced occasionally.

 

My bet is also on old crunchy connector or wires, and many will tell you OEM is the best route for any sensors or solenoids on a Lexus.