VREN

Hi, I'm looking for help. We got a 1991 ls400 and recently it went into limp mode with unburned fuel smoking out of the exhaust. Car won't accelerate past 5pmh and rev past 1500rpm. No check engine code. When I try reading it with obd 1, the check engine light just flashes really fast. I got 2 ecu units from a pick n pull, both from wrecked 91 ls400 with the same part number. Nothing has changed. Has anyone experienced a similar problem?

Hi, I bought a 1991 ls400 with 150,000 miles and recently got myself a check engine light. Code 25 and 26. The car would shake on idle as well. I went through forums and decided to replace spark plugs and wires. That didn't help so the next step was O2 sensors. Replaced both upstream sensors with Denso branded ones. The car ran perfect after that for about 2-3 days and then the problem came back. It wasn't shaking as bad at first but now we are right back where we started. I know coolant leaking in the exhaust can cause O2 sensors to die and I did have to add some coolant a few weeks ago when my light came on. (the shaking problem was already present at the time). Thanks in advance!