brokevip

When driving my 1998 ls400 today, every time i would try and accelerate a decent amount, both p0330 and p0325 will pop up and have to be cleared so i reset my ecu and filled up with fresh 94 to see if that would help, and it stayed the same. I didnt change anything or replace anything before my last drive. Its barely driveable right now as every minute or so it will go into limp mode and i have to clear the codes.

Both knock sensors, oem from a lexus dealership, and harnesses were replaced not even 2 months ago

Could this be an ecu problem or will i have to replace them again for 200+ each, or could it be something completely different

brokevip

Also my idle isnt super smooth when in drive, it idles pretty low and shakes a tiny bit. This might be because my cv axles arent in great condition though

Yamae

Sounds like the vacuum leak problem. I'd check the fuel trim using a scanner capable to measure it first.

brokevip

All my hoses were replaced about a month ago, so im not sure if it is a vacuum leak, but ill get a scanner than can read fuel trims and get back to you on what it says

aptoslexus

The knock sensor harness is no longer available, so my question is, was it really replaced? If you've got two new sensors in there and you're getting codes on both, I suspect a wiring issue.

CLLEXUSS

Take it back to the stealership, I mean dealership, those are knock sensor codes

brokevip

The last owner who claims to have done it said this “I routed a shielded wire from the ecu to the engine lift hook which has a knock sensor bolted too it” does this sound legit or is he making it up. I’m still pretty new to working on cars so I’m not 100% sure

CELSI0R

The "engine lift hook" is closer to the right valve cover than it is to the knock sensors.

The knock sensors sit in the valley of the engine block:
https://us.lexusownersclub.com/forum...sor-00-ls-400/

The harness isn't supposed to route near that hook. It's supposed to come through the middle of the engine from the back

So what he wrote doesn't sound right. And the knock sensors don't bolt into the hook, if that's what he's saying.

brokevip

I see. Tomorrow im checking my spark plugs and checking if its running lean. if its not either of those i think i found my problem.

If it is the wiring whats the best way to go about getting that fixed

thanks for all the insight guys

aptoslexus

Since the previous owner seems to have jerry-rigged a failing fix for this, you're going to have to figure out what he did from the ECU to the knock sensors and repair that. Possibly an aftermarket harness can be used, but you're going to have to investigate the extent of what's wrong and I would also check that the knock sensors are indeed Lexus sensors and not some aftermarket junk.

brokevip

When looking over the car today i found and replaced one bad spark plug and a cracking hose that i had missed when i replace all the other vacuum hoses. After test driving it seems to have fixed the problem as no codes popped up but if it does come back ill have to crack open the manifold and look at the wires etc. ill also have to watch out for if that spark plug goes bad quickly as that might be a bigger issue

praying its all good now though