bcorey

Hi All -

I've read several posts with regard to knock and 02 sensors, as well as MAF issues but honestly don't know where to start with trouble shooting? I don't have a CEL and no other lights have popped up - this issue started several months ago and I've tried different brands of gas to no avail. I always run premium btw - I'd like to try and get this fixed as I don't want to have any long term effects on my engine - it's a 2001 with 157K -

If I take it to the dealer, I'm worried I'll get some inflated or improper diagnosis but I'm worried about not doing anything as well - can someone point me in the right direction please - thanks in advance!

bootnylee

just have it checked then you decide from there


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Lavrishevo

iTrader: (1)

What % of ethanol in your local fuel? Is your premium 93 or 91? Pre-cat OEM 02 sensors are not too expensive and something you can replace yourself. That and maybe a failing water temperature sensor. Not the one that runs the gauge, the one that runs to the ECM. I would start with the temp sensor considering how cheap they are.

ancdmd

let us know if you find anything that rectifies this issue or if it gets worse...

ancdmd

Don't assume it's actual engine knock. I'm no expert but I feel if the fuel/air mixture was off enough for the knock to occur, the CEL would illuminate. I have had a pinging-type noise for a couple years that has gotten pretty awful (I now know it's not engine knock but techs thought it was in the beginning), and I went through many bottles of fuel system cleaner, changed gas brands, etc to no avail. If there's one thing I've learned from chasing this problem I have is that throwing parts at the car without a definite diagnosis of the real problem is only going to cost you a lot of money without fixing the issue.

BradTank

It's well worth $100 or so have a Lexus dealer diagnose it and you can take it from there. They have have diagnostic tools beyond just simple OBD code readers that can really pinpoint the problem.

You don't have to have them service it if you think the price is too high or want to do the work yourself, but shotgunning parts gets a lot more expensive than $100.

I usually avoid dealerships also in order to be economical, but when I have a real "mystery" problem, it's well worth paying them to diagnose.

My last issue was the car was hard to start and sometimes stall out at a stop, but it threw no codes. It turned out to be the fuel pump. I'm glad I didn't throw a lot of sensors at it first.

ancdmd

Any solution to the pinging problem? My car does the same, has been for quite a while. I always use Shell V-power, BP premium or Chevron premium, and have run several cleaners through the car over the years with no change in the pinging. I fixed an issue with the driveshaft that was giving me a similar noise but the pinging from the motor is still there, mostly under throttle at low rpms or heavy throttle across the rpm range. Just replaced the MAF and that didn't really change anything either. NoCELs, ever. Frustrating.