Hi, new to this forum but 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?

 

It is really not easy to tell what's wrong, especially without being able to see the car

Have you opened any of your ECUs to check the condition of the capacitors? All 3 could be bad

If they all check out ok, then the problem is elsewhere

also does this problem always happen? Does it ever resolve? Under what conditions does it happen? (Temperature, driving, in gear, etc)

 

the ecu is being tested right now. This limp mode is constant. Nothing changes. I start the car up and i cant really drive it. Unfortunately, bay area, California doesn't have a lot of good mechanics.

 

one thing I thought of now - do your catalytic converters glow red after the car has been running for a little while?

If they do, your catalytic converters might be clogged

Next time you run the car, have a look underneath. Probably needs to run about 10 mins