Hi All,

I am trying to fix my sons 99 ES300 and have gotton to a point where I need some guidance.

Started with the CEL and TRAC OFF lights. Read the codes and had misfires on 1,3,5. Brought the car to a dealership and they confirmed it needed plugs and coils. I bought and replaced all plugs and the coils for 1,3,& 5. Cleared the errors and gave the car back to my son. He drove it about a day and the CEL and TRAC OFF lights came back on. I read the codes again and there were more than the first time. P0300,0303,0305,0171,0136,1133. I guess I can assume the misfire codes for random and 3 & 5 are not due to the plugs or coils. I am not sure which of the remaining codes to tackle first. Which is the cause and which is a result. Is there an area I can focus on that ties these errors together or am I looking at solving multiple issues?

I reset the errors when he brought the car back and drove it around a bit. No CEL came on but I ran a check of the codes and there was one pending, 0171. I read in another post about checking vacuum lines for this code. Is this a starting point?

Thanks in advance for your help.

Rick

 

Checking for loose vac lines etc is always a good idea. It only takes a few mins and is time well spent.
You did not mention mileage, did you replace the fuel filter? Also, and by far the most important, Did you gap the plugs before installing them? I used to believe that gapping was not critical. I now firmly believe that it is, (proven beyond any doubt to me).

 

I'd let the vehicle be drive around a bit more before making any final assumptions. The vehicle may have to clear the gunk out (due to the previous misfiring problem) and since you mentioned all you get is a pending P0171, you may just need to let the vehicle be driven for a bit and then verify if anything else is occurring (i.e., any more check engine lights).

 

Thanks for the replies.

Some more background info. We took the car off the road in March because it would not pass MA inspection with the CEL on. I have been waiting for the time and weather to work on it so It has been idle for a bit. It has 116k miles and I have not changed the fuel filter yet. As for the plug gap I purchased what I was told was the higher end plugs. Bosch Platinum and Iriduim Fusion model 4501. It has 4 grounding posts and I was told gaping them is not possible.

When I drove the car after resetting the error codes it ran a little hesitant. Possible bad fuel? I had a problem with my motorcycle this spring due to the ethanol in gas. Does anyone know of this being a problem for cars too?

As for checking the vacuum lines for leaks, any suggestions on where to start?

Last question. Is the TRAC OFF light a result of the CEL or the other way around? Are they independent of one another?

Thanks so much for the help.

Rick

 

I used a 4 pronged torquemaster plug on my RX300 (you're right, you can't gap them as a result), but haven't had issues with those plugs either when I was in Mexico (where the gas was crappy and higher in sulfur) or now here in Florida. Otherwise, I'd stick to Denso or NGK.

One other thing, if you haven't been driving it for a while, what you mentioned can be quite normal with hesitation, even a bit of black smoke is not out of the ordinary.

How many tanks have you run through it since you got it back on the road and what type (octane and brand) are you using. You might want to try some injector cleaner.

Using the TRAC comes as a result of the CEL. I have seen this a common issue in later model RX300s (don't have TRAC on mine).

I don't know offhand if the vacuum leak is the issue at this point in time.