I have a 99 es 300. I bought it a few months ago and have not been able to enjoy it because I keep getting the run around. Some one told me to sell my car but I will not give up yet. So here is the problem: the CEL and TRAC OFF lights are on. Now under the hood shakes really bad when at a red light and the CEL blinks until I drive again. The code I am getting is P0300 which says something about a random cylinder misfire. I have also had the solenoid valve code as well. One mechanic at AAMCO said I need a new transmission. Another mechanic at a different shop said I need a new engine. I am sooooo completely lost. My car's RPM dial fluctuates from 3 4 5 when I am cruising at 60 mph. I am totally lost. Please help.

 

arent these the symptoms of a knock sensor? correct me if im wrong please folks.

 

Is it just one cylinder misfiring, or a bank? I had a similar problem before but I don't remember what the code was. I had a rough idle with the CEL and TRAC lights on. Turns out it was a bad coil pack.

 

sell my car

 

Why don't you simply take it to Lexus and get a diagnostic. Money well spent. I had a similar issue and I needed a new fuel injector.

 

the misfire requires a tun up, i would recommend you to start changing the spark plugs on all cylinders (even if they are not at fault, recommended especially if the old owner did nothing), if that doesn't work change the specific ignition coil (whichever cylinder misfire # you have), the the 3rd option, which is more expensive are the fuel injector(s).
corrct me if i am wrong.

 

agreed!!.. dont mess around with things if its not on here.. you dnt want to kill ya bby. lol

 

P0300 Diagnostic Code - Random Misfire


Technical DescriptionRandom/Multiple Cylinder Misfire Detected

What does that mean?Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.

A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.

Symptoms

Symptoms may include:
•the engine may be harder to start
•the engine may stumble / stumble, and/or hesitate
•other symptoms may also be present

Causes

A code P0300 may mean that one or more of the following has happened:

•Faulty spark plugs or wires
•Faulty coil (pack)
•Faulty oxygen sensor(s)
•Faulty fuel injector(s)
•Burned exhaust valve
•Faulty catalytic converter(s)
•Stuck/blocked EGR valve / passages
•Faulty camshaft position sensor
•Defective computer

Possible Solutions

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

 

Really "no money spent" I have had a few or more like two issues where I was just completly lost It could be this, this, this so just called lexus told them my prob and they checked it out and did the diagnosis and said it would be $550 to fix this, this and this, and told me exactly the prob, so I said ill come back later, so they dont charge up front, because they expect you to get it done at the Lexus Dealer, so I went home and cleaned this and cleaned out that and prob solved

 

This is probably the best answer here. Random missfires due to lean fuel mixture is the place I would start. Closely inspect all vac lines, and hoses for splits and cracks (pay especially close attention to the ends of the hoses).
You did not mention the mileage, what is it? You have a 99, have the spark plugs been replaced? and the fuel filter?