mrsincere

I have a 2004 LS 430 with 132,000 miles on it. The car is not driven much, it sits in a car port at a friends house in Florida. The car ran perfect the end of 2018 before it was parked for a very long duration. It has only been started 3 or 4 times in the 2 years following. August of 2021 I started the car and in minutes the CEL,Trac OFF ,and VSC lights popped on. Also I noticed that there was a knock in the engine. Not that noticeable at idle, but definitely audible when driving.

When driving the power and performance was non-existent. The car struggled to get up to speed, and the engine was very noisy, like driving a diesel truck. I went to work on diagnosing the problem. My OBD scanner gave me the p0328 code. Knock sensor bank 1 high circuit. I tried resetting it over 2 dozen times, to no avail., lights came back on.

Researched possible alternate causes of a knock sensor code other than failure of the knock sensor itself, and found out that bad fuel could potentially cause a problem. In my case it made sense, the car had been sitting for almost 3 years with the same fuel in it, in hot Florida. Im thinking the fuel eventually became contaminated with water, dirt or whatever.

I started to work on the problem myself. 1st I put in additives in my tank. Seafoam, techtron fuel inj clnr, gumout, water removal products, and I went through a few tanks of gas. Additionally, I had my throttle body cleaned out ( a lot of gunk right at the throttle plate ), replaced the spark plugs, air filter. I changed the oil and added seafoam to my crankcase. Changed the oil again with no additives in the crankcase. Was going to add some Marvel Mystery Oil to the crankcase, but thought I'd wait to see how the other additives helped. I also changed the gas cap, with one from the dealer. I really believe my old cap was bad. Another thing that was quite apparent, I was using gas like crazy. I could run through a tank of gas within a day and a half.

Almost a week later after the things I did, the car started to drive a little better. The acceleration and shifting was a little better. The car still struggled to get into it's highest gear when I tested it out on the highway. The knock noise was still there, at initial acceleration, but smoothed out above 40mph, and unheard at highway speeds. Transmission seemed to be stuck and not in it's highest gear on the hwy. Of course my warning lights never went out. My code reader could erase the codes, but the minute I started the engine, the lights came back on.

The last thing I inspected and replaced was the MAF sensor. The one that I removed, you could see obvious grime and dirt on all of the contact points. After replacing the sensor, and driving around with more fresh 93 octane gas, the car idled a lot smoother, the knock was much less pronounced. After a while I noticed that I could take off from a standing stop, and watch the rpm gauge go through it's highest level for each shift of the transmission. The car was acting like it was recovering from it's power loss. On occasion it would buck if you try to mash the gas very quickly while in motion, but the car ran a lot smoother at speeds above 30mph with minimal knock noise.

Im wondering if after all of the things Ive done that could relate to poor engine performance and the lights coming on, that maybe the car is on the way to running normal again? That maybe the bad fuel, bad gas cap, dirty throttle body, clogged fuel injectors, gummy moving parts in the engine and injectors from sitting too long, dirty maf sensor, dirty air filter, old spark plugs etc all were a contributing factor leading to my knock sensor to activate. I had to re park the car the end of August 2021, but I am going back to Florida to resume attending to the car. I am hoping that once I start driving the car again, that the cars systems will reprogram or reset itself.

Some of my research leads me to believe my old MAF sensor, the bad gas, the engine not being used for almost 3 yrs are the major factors leading up to my knock sensor activating. After reading my experience, does anyone have any thoughts, advice or experience to share with me? I truly believe once I start driving the car again very soon, the car may slowly start acting normal. Oh one last thing. Where the car is parked, I believe rodents are a problem with the cars parked there. I hope rodents didnt get to any wiring to my knock sensor. I do not see any droppings underneath the hood. I also saw evidence of a wasp nest formed at the air intake in the front of the car, along with a large rock just under the air filter. ( how could that have got there?) The last time I drove the car ( from August 6th 2021 until August 28, 2021 ) , I swear the power and acceleration seemed to be coming back.

Bocatrip

Bad gas is certain to be contributing to your issue. If you are not making the progress you'd like, I'd give lexus a shot with their diagnostics to get to the route of the problem. It might be worth the investment. If the gas tank was not dropped and cleaned, it might have contaminated the injectors and everything fuel related. Good luck and let us know how you make out.

mrsincere

Thanks for your reply/input. Correct, my fuel tank was never dropped or manually cleaned. I just started solving the problem using additives, and attending to other obvious things that I could do without a mechanic. The last thing I did was to replace my MAF sensor. After doing that, I noticed a return of power when accelerating from a standing stop to 50 to 60mph. Maybe the additives helped, and replacing the MAF sensor helped? When I get back to the car next week, if I do not see a significant improvement from driving it, and/or Im unable to get my dash lights to reset, going to the dealer will have to be my next move. I will definitely report back in case someone else may be going through the same thing.

mrsincere

Turns out my problem was an electrical failure not bad gas. Took my 2004 LS 430 to a repair shop. Diagnosis p0328, which I already knew. Before the job was started, the repair shop predicted that rodents had got up underneath the intake manifold and made a nest and chewed on the wires. That is exactly what was found once the manifold was taken apart. The repair shop claims the affected sensor was also damaged along with the wiring harness. They installed 2 new Denso knock sensors, and rebuilt the damaged wiring harness to KS bank 1.

Good news is that there were no other problems with the car. FWIW the 1st estimate for the KS work was by Meineke in Tampa. They wanted $944 to replace 2 KS, gasket, and the labor. The place that did the work wanted $1,027. I went with the 2nd place even though they wanted more. For some reason I felt more confident with them. They charged me an additional $30 to repair the damaged wiring harness to the KS. For a grand total of $1,060.

Additionally, I bought 4 new tires because the set on the car was dry rotted with cracks. Not road worthy. But now? The car runs like it may have when it left a Lexus showroom 17 yrs ago. Lastly, my next move is to get rodent repellent and pack it well underneath the hood when I park the car for long periods with the battery disconnected. If it hadnt been rodents causing the damage my car would have been fine for years to come except for maintenance.