Hey, I have a 98 ls400 and was just wondering if this sounded like an ecu problem and it would be time to rebuild it, heres the symptoms:

• Randomly code p0172 or p0330 will pop up then go away for a week or more after clearing them
• car will sputter/struggle when trying to start with the engine warm
• car will jerk off of a stop if im not super easy on the throttle
• car will occasionally have small jerks when shifting
• car will shift into 2nd at 3k rpms for the first time on every drive then be normal after
• car will go into limp mode whenever p0330 pops up then be fine after clearing
• poor gas mileage

If i remember more things ill post them. When i looked at the ecu it looked all fine with nothing leaking, but im just wondering if its something i cant see. I can post a video of the ecu if that would help.
thanks

 

Quick search I came up with this for the P0330 Code.

 

 

The knock sensor was replaced around a month ago and after i cleared the code it hasnt come back yet so im thinking either the connector is bad, or the ecu is sending random codes

 

Okay well, it looks like there are two knock sensors. I found a thread here on the forum and one reply went like this;

"There's two knock sensors. Good luck finding the wiring harness. It was unavailable when I changed my knock sensors. Don't use aftermarket knock sensors; they'll throw a knock sensor code. And if you're not throwing a knock sensor code, you might reconsider changing them when you see how much Toyota charges for them."

So the locations of where these are at are a bit involved too. The wiring harness for the sensors is apparently also a recommendation to replace when you are in there but hard to find I guess.. These cars don't seem to like parts store generic name sensors either from what people are reporting. I saw another commenter say not to drop the sensors on the ground, that could also damage them. So maybe if you can clear the codes like you did, if it doesn't come back you might be good. The ecu's from what I understand in the 2nd gens are better than early 1st gens regarding the common problems, however, it might be the ecu, it's just that you want to go where the information is pointing you to. If you have information that is pointing you to the ecu. That's what I would think anyways.

 

So this is a basic parameter of testing an ecu with a diagnostic scanner which is getting a bit more technical but if you are up to it why not.

 

I pulled the ecu and it looked all fine so ill check out the knock sensors next. ill update on how that goes

 

edit.........

 

I worry that it's a fuel injection related problem and I'd check the fuel trim level using a scanner which is capable to measure it. The measurement needs to do at variety of situations like when the engine is just started up, while warming up and after fully warmed up.

Your words "car will occasionally have small jerks when shifting" reminds me of a failing ECU but the random code p0172 or p0330 denies it. A failed 98-00 ECU seldom behaves like that way, in my experience. I mean there is no code but only the shifting is rough.

 

I originally thought it was a leaking injector but when i tested fuel pressure it was fine and held pressure after shutting the engine off.