idream08

good day, don't know if this should be in the maintenance section if so feel free to move and my apology. This is going to be a long post because I want to be clear as possible......Ok i've had my es300 for over a year, it has around 162k, when i bought it had 151k. one owner the dealer told me this guy just had that 100k service thing done. Anyways this car has ran super smooth for the entire 16months i've had it. All i've had to do was oil change, brakes, and tires! about 4 months ago after a 700 mile trip, i came back home and a couple days later i noticed when the rpm got a little over 2, especially at slow speeds--the car would sort of vibrate, my girlfriend says it feels i'm running over something or something is stuck in the tire, it's like a shake or something only when i'm going at a slow speed and the rpm gets at or a little over 2. Well this was during the $4 a gallon gas thing and i was using several different gas stations on my trip, i've always used premium except 1 time when there was a shortage in Atlanta. Anyways after this vibrating like problem (wish i could describe it better) i bought some stp gas treatment stuff. this was 4 months ago and it erased my problem! everything has been smooth sailing the past 4 months, i've took the car out of state and everything. Well today that little annoying shake when the rpm gets around 2 started again. Well like the first time it started a couple of days after a long trip. So I go to pep boys, I see the same stp gas treatment stuff that saved me last time, but NOOOOOOO, mr. curious had to ask the rep what was the best one they had--i really couldn't remember if i had bought stp gas or stp fuel injector cleaner....anyways he tells be Lycus fuel cleaner will do both. So i bought a little bottle with a near full tank and five minutes later for the first time since i had my Lexus, i saw the dreaded Check Engline Light.......... It blinked about 5 times and went away. Curious, I took the long way home. I drove the car slow, then I drove it fast, i did fast take offs and slow take offs--NO PROBLEM. I turned off the radio and all was quiet, gages were normal, i even pushed 90mph and i rarely do that----i was just doing some self troubleshooting or trying to listen for any bad sound from under the hood, i wanted to see if the check engine light would come on again. It never came back on and I drove for 30 to 40 minutes. The car shifts quiet and smoothly, except when i'm going slow when the rpm is around 2. My thing has always been don't take it to the shop if the sign isn't frequent. I can't take it to a shop if the engine light isn't on, and if it doesn't constantly shake. I've been through that before with other cars and all they seem to do is guess. Anybody know why the car vibrates or shakes around 2 on the rpm and why my check engine light blinked 5 times? thanks

Lexmex

Sounds like a misfire. I'd go to an AutoZone where they can read the code for free, then let us know what the code was. It's still in the computer even if it ain't blinking or lit up.

idream08

thanks for your response, will try to get to autozone within the next couple of days and will post the results. "misfire" what's that? and you say even if the check engine light isn't on, they still can tell? thanks

Lexmex

Most likely cause was some bad gas that caused and issue with the combustion. I've had a misfire with my RX300 back in Mexico. My own fault because I sprayed too much carb cleaner when I was cleaning out the intake manifold and one of the ignition coils (shown below) went dead. I had to modify a coil from a Camry, because when I lived in Mexico there was no Lexus (there still isn't yet), but I got the coil to work. The ignition coil is the most common cause of a misfire (in terms of being bad or going dead) though bad gas, a bad spark plug (dirty, bad gap) can also cause an issue, even a voltage issue can sometimes affect this. The ignition coil goes on top of the spark plug.

Lexmex

Yeah, they can still tell, because the code remains in the computer. Sometimes the check engine light can turn off if the computer sense everything returned to spec so to speak. I used to have that issue in Mexico a lot with P0171 lean error codes that would make the CEL go on, and then a few days later, it would go off. I wound up getting and OBD2 scanner (cheap and they're under $100 USD like the one below) just so I had it handy.

Lexmex

The codes you are likely to see are:

P0300- random misfire (I think this one) and then any one or or multiple of the following
P0301
P0302
P0303
P0304
P0305
P0306

Just pay attention to the last number as they relate to a misfire by cylinder number.

1, 3 and 5 relate to the rear bank (back of the engine) from passenger side to driver's side

2, 4 and 6 related to the front bank (front of the engine and like photo shown above with the coil) from the passenger side to the driver's side.

I also think a P0171 code might show up, but don't worry about that one, it often shows up with certain engine codes related to combustion issues.

Parker Gen

Does that OBD2 scanner work on Nissan as well? Or would I have to buy a different type?

Lexmex

Depends on the year of the vehicle and if it has OBD2, generally 1996 model vehicles and later have OBD2. This is where the port is on my RX300. My girlfriend has a 99 Ford Expedition and it's by where your right knee would be.

Parker Gen

Oh ok, cool.

98_es300

Lexmex: What was the resolution to your P0171 lean error? I get the same code on my car?

Thanks

Lexmex

This is the magic list of possibilities and my comments:

-air intake hoses (check the ones by the airbox and the IACV valve)
-fuel line pressure/injector blockage (run some fuel injector cleaner through the system, Redline fuel system cleaner (Pep Boys has it) is the best stuff in my opinion in an all-around cleaner
-A/F sensors (doubtful), but sometimes as a result of a crack somewhere on the exhaust itself, either right off the manifold or underneath the engine), this doesn't necessarily mean something is bad with the sensor, just that it detected something out of whack.
-MAF sensor (needs to be cleaned)
-engine coolant temperature sensor (rare), because other codes P0115, P0116 would be involved
-exhaust system- as mentioned above by a/f sensors

idream08

thanks for all the responses again, just getting off work, today the car ran smooth, no shaking (feels like the tire is running over a crazy bump in the road) when the rpm got to 2 and no check engine light flashing. nevertheless i'm cautious and watching for the light, lol. I guess it let me know my Lexus isn't immune to the world. I've never had any problems out of this car (161k) except tires and brakes. But, if this shake when the rpm gets around 2 and check engine flash wasn't a coincidence does it sound like it could be a major problem or expensive problem? like i said everything is shifting smoothly, no straining, no loud noises, no increase in the temperature gauge, or anything. Maybe the lucas fuel injector cleaner had to sink in overnight?? i hope the problem is solved but i'm alert and ready to take to a shop if needed. thanks

Lexmex

Did you get a chance to have the codes read?

idream08

didnt get to autozone today, had a few other stops to make today. Should be able to get there tomorrow. thanks

idream08

good day to everyone, I went to autozone and the code is P0301 he said it was a misfire, he said something up the 1st cylinder spark plug is going bad or something and that a tune-up will fix the problem....i was trying to ask a little more but he seemed to be in a rush.