2002 Lexus had poor acceleration problem and was diagnosed with needing possible reflashing by a dealer with the equipment to do it. then I used supreme grade gas and a cleaner additive and the problem went away basically. since its 2002 my brother says to reflash it, but not every mechanic does this in their shop.
21+ year old car, if dealership can reflash, I can not see where that will hurt. If your vehicle call for 87 octane, going to 93 octane does nothing. At next fill up, another bottle of SeaFoam or Techron (Techron is considered to be more powerful for cleaning dirty injectors) should be all you need, only use a TopTier rated gas.
You never stated whether or not your CEL was on.
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That engine requires gas of at least 91 octane, so if you had been running it on “regular” gas, that could explain a power loss. The use of a cleaner additive may have helped by reducing a build-up of gunk in the fuel system and on the valves, but if you want to keep the engine performing properly, you need to use “premium” gas, and–as Purebred mentioned–using gas that is certified as Top Tier will help to keep the fuel system and the valves clean.
Edited to add an additional thought:
Because the Lexus Owner’s Manual clearly states the engine’s octane requirement, I’m assuming that the OP bought this car fairly recently, and that she hadn’t taken the time to read the manual. This would be an excellent opportunity to look at both that manual and the booklet detailing the manufacturer’s maintenance schedule.
That maintenance schedule will mention some very vital procedures, including the need to replace the Timing Belt every 8 years or 100k miles–whichever comes first. If the timing belt is beyond those intervals, you have to be aware that when the overage timing belt snaps, major internal engine damage will take place, so please be sure to verify whether the belt is due for replacement.
Visual inspections tell you very little, so you need to see a hard copy of maintenance records in order to see if the engine is due for a belt replacement. The belt tensioners should be replaced at the same time.
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hi guys and thanks for all that excellent feedback.it had a new timing belt in 2012 and I’m selling the car, so not going to fix it up anymore, but now I know every 8 yrs. or 100k miles it should be done, however in 6 yrs only put about 6k miles on it tier. CEL is off now. acceleration is very good. not sure if I have to do a reflash as the CEL went off.
Timing belt replacement is based on time or mileage, whichever comes first. It has been 11 years since the last replacement and it’s overdue despite the low mileage. If you are selling in the next week or two you might get away with it. If you will wait several months, I’d get it done now. It’s. Selling feature to show that the work is done. If you don’t replace the timing belt, I suggest that you sell it to a used car reseller like CarMax. They are orofessionals and should know to ask about it. If you sell to a private part, IMO you should tell them it neeeds a new timing belt. They in all likelihood won’t know to ask.
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Since you did two experiments at the same time, there no way to tell which of them solved the problem. Case 1: It’s possible your engine was pinging when running on lower octane gas. That’s supposed to be prevented by the computer reading the engine ping sensor signal and adjusting the ignition timing, so it is possible that sensor is no longer working. Case 2: It is possible you had slightly clogged injectors causing a misfire. Now injectors are clean so you can go back to using lower octane.
Before deciding on the reflash, yes or no, suggest to post here what problem(s) the reflash is claimed to address. I wouldn’t reflash just b/c it might help, b/c reflashings adds a lot of variables to what is already a complicated diagnosis.
For best Karma, suggest to inform buyer about timing belt age situation.
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+1
Bad Karma will follow her all of her days if she foists-off that badly-maintained car without informing prospective buyers that it is overdue for a very vital maintenance procedure.
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A lot of Toyota engines have non-inference designs. Not sure about 02 Lexus IS 300.
I’ll mention to the new buyer the timing belt is at least due for inspection, but after fixing the air conditioner at $450 just today, I’m not prepared to pay another $600 for a new timing belt. so again thanks for scaring the crap out of me guys! I have lots of potential buyers wanting this car because its a 300 IS engine. likely as not a mechanically inclined buyer will show up so he can fix stuff himself. I like the way its running so fast now, that I’m thinking of not selling it.
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A visual inspection means next to nothing. A timing belt that looks “okay” can snap the next day, with very serious consequences. That is why they are replaced proactively–on the basis of either odometer mileage or elapsed time, whichever comes first–and your belt is at least a year past-due for changing.
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