clapped90ls400

I’ve been having weird problems with my (90) first gen ls400. First off there is no rev limiter, now I don’t know if that’s because of my tac not reading correctly or if it’s a different issue. Secondly my top speed is reduced, I’ve been reading that these cars can reach a top speed of “155mph”. I’ve been trying to push it to that but it only reaches to 110-115mph. I have no clue if those problems are related but it’s been a pain to figure out. I don’t know if it’s ecu or something small. All advice would be appreciated. Thank you

400fanboy

What do you mean you don't have a rev limiter? If you were actually going beyond the rev limit, you wouldn't have an engine anymore.

What other testing have you tried? There is not much information you've provided. Lower top speed = the car isn't making the power it should = engine issues. Or maybe ECU. Who knows. Need more info\testing.

cj98ls

How long have you had the car? Is the rest of the car (tires, suspension, brakes) in any kind of shape to deal with high speeds? The word "clapped" in your ID wouldn't fill me with confidence that the car is capable of too much, and 110 mph in a clapped out (if that is your meaning) 30+ year old car sounds a bit suicidal or at least terrifically careless. But then again I'm getting to be an old fart and have left my daredevil alter ego somewhere behind me. If I squint I can just about make him out in my rearview...