archangels

i noticed when i first bought this when i accelerate about low throttle 10mph -35 mph i get this sputtering sound the best way i can explain it is if you were driving stick shift and you are suppose to be in 3rd gear but you put it on 5th gear you know what i mean wrong gear sputter rattle sound? is it possible a/f sensors and 02sensors that are bad can cause this after more acceleration it disapears the sounds, only on low acceleration, feels a lil hesitant in low accelaratrion then picks up with aggression, i checked my throttle cable it was stiff enough so i was thinking changing my a/f sensors and 02 sensors... but would ask expert advise on that sputter rattle sound thanks

Lexmex

When do you get this sputter sound, shortly after start up and when you are on the road?

archangels

lex mex i get the sputtering sound when i only on the road acelerate about sometimes 15mph to 40 miles per hour after that it stops, i bought 2 a/f sensors and an 02 sensor today, i was thinking maybe my sensors was not functioning right so maybe the engine needed more fuel and maybe gave more air less fuel? hopefully that p0171 and p0174 does the job when i replace the 02 and 2 af sensors, but i was thinking that sound probably happens because not efficient air and fuel mixture? best i can describe it is if i had a 5 speed manuel stick shift and started 2nd gear instead of first it make a sputter rattle sound as if a chunk of cat piece broke but not sure but sounds like a stone in a soda can shaking sound

MellonC00

sounds like knocking.... just to rule out the fuel problem, try using 91 or 93 octane for a while, then go back to whatever you were using before.

MellonC00

more detail on my previous post...

I had the same "rocks in coke can sound" on a previous Lexus I used to own. Using 91 octane helped but eventually my check engine light came on. It turned out to be a mass airflow sensor or MAS.

Lexmex

Hard to tell what this is. You might want to take a video of it with the sound.

archangels

ooohhh so thats what people say about engine knocks and pings sound, it only happens when i use fuel system cleaner, fuel injector cleaner, and throttle body cleaner, i was empty after using the detergent fuel cleaners, i slapped a full tank of 91 octane, didn't hear it no more, i guess thats why folks says not to use low quality fuel plus later can harm your engine if you put crappy fuel, it can cause more carbon build up, i will try 89 octane fuel after this runs out and see what happens , i used prestone fuel system cleaner , then refilled with stp fuel injector cleaner, i will use every oil change. but i do notice after used fuel injection cleaner and fuel system cleaner the rx felt strong,was smoother shifting, faster acceleration, i guess after i maitntain this rx everything should run strong and reliable for years to come, this is my first luxury vehicle and love it, i think lexus new models productline are all nice as well... lexmex as for the magnaflows which ones better the 2 tis at the end of muffler or 1 tip straight through? is there a difference? i was 3 minutes away from magnaflows corporate business, family members were saying that i would look foolish addeding a muffler with sound, and i was debating most of the week end i couldn't hear was gear i am on, plus less restriction+ equals better flow and saving more gas, hearing what gear you are on (that was tough my rx was climbing a steep hill i could not tell if i should step on the gas pedal or if it was already shifting , so i am really considering a freeflow straight through magna flow for the benifit it provides, i really felt the restriction and it bothers me i like to hear what gear im on plus save gas, like the sound, plus less restriction equals less strain on the motor, i wanted to buy the magnaflowsfrom corporate headquarters but they told me that only their dealer distrutors can sell to me not them as the manufacturer. so i i was told if i slap on a 2.25 magnaflow i could notice a loss in climbing mountains with rx? is that true? all i want to do is flange back and leave everything else on. i was looking to go 2.25 in and out polished maganaflows either 2 tips out end muffler or 1 straight through but i want to know is there a better one then other or both the same just diffrent design? thanks i bought 2 af sensors and an 02 sensor denso originals cost me a fortune 389.04 dollars hopefully i will incresae more gas mileage and better performance and etc i guess i will be only using originals as some of the forum members say its best.. thanksalso normally when do you change 02 and af sensors?

Lexmex

Get rid of the exhaust restriction and your vehicle will be happy. I am remember going up hills/mountains in Mexico that were as steep as can be with the OEM exhaust, it was like a cow walking up the hill. In fact an embassy employee there with an RX300 from Virginia told me once that was exactly how he would describe it. Direct flow exhaust and the RX was feeling much happier.

archangels

ok i am 95% sure i will go flange back take oem off with placement of magnaflow... will i notice a big difference? how much gain with this, also there 2 style 1 pipe 2.25 inch straight through, and 2.25 with 2 tips side buy side the tips are independant tips not the y type tip , which is better? is that best way to go from flange back not cat back, and leave resonator didn't you say oem piping was 2.25 inch anyways? thanks ron

Lexmex

If it is a direct flow muffler, you most certainly will. At the high end, depending on its design and width of exhaust passage, you can see about 12 hp with this. I have read of a few Toyota Solaras that have gone on a dyno (the ones in question have a similar 1MZFE motor to ours) and they run on average with that based on what I have seen after installation of just a direct flow muffler. A direct flow muffler was what pushed me under 19 seconds in the 1/4 mile back in Mexico City, everything else eventually got me under 17.

I would get the 1 in and 2 out y type if you can get it. Cat back is the best, but requires considerable work so as not to have the loudest RX on the planet and get nasty rasping sounds. In addition, when you do cat back, unless you increase the diameter and/or divide the piping like I have it into two, you won't see much gain there. The key for power is to remove restriction and increase diameter.

Yes you have 2 inch piping around there, that is why I went twin 2.25 inch after my resonator (which I hope to remove sometime today or this week in place of another one or glasspacks).

Sox2grave

Did you ever get a response for your problem..reason being..I have the exact problem (2001 with 65,000miles) and took it to the Lexus dealer in Va and of course the problem could not be duplicated..very random noise as if the wheels were slipping and finaly engaged. Also, an associted problem of wheel crunching noise when making a sharp uturn. Again, not consistent.
Any ideas?

archangels

it was engine knock after cleansers finished and i added 91 octane it vanished, engine was happy and running stronger and faster response to acceleration on demand

JM5879

im pretty much getting the same problem too. if i let the car sit for acouple of days i dont notice the shudder. but the longer i drive the car the shudder becomes more pronounced. especially when going up an onramp to get on the highway. the example of shifting into 5th gear instead of 3rd gear fits perfectly to what im experiencing.

smerre01

Look guys, I know this PROBABLY isn't the fix to your problem, however the Rocks in a Soda can reference jogged my memory. My RX did this same thing made horrible noise at low speeds, sluggish, etc. Finally figured out that it was the exhaust bracket holding the front pipe to the CAT. It was loose and vibrating around, making a terrible sound. I don't know if this is any of you guys problem, but I wanted to offer it as the soda can reference jogged mine memory.

JM5879

nope no soda can sound. just really sluggish and shudders like if you were shifting into to high of gear..

i know when i had the soda can sound it was because my MAF was dirty. sprayed alittle electrical cleaner on it and problem was gone.