'02 ES300 lacks power, runs a little rough, seems to have a lean surge when accelerating from 5mph-10mph(especially after decelerating and not coming to a complete stop), seems to miss once after making a turn and attempting to keep acceleration constant, has a new MAF, and both of the A/F ratio sensors have been replaced. There are no trouble codes or engine lights on. Has anyone diagnosed similar symptoms?
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Is the condition exactly the same as before replacing the mass airflow sensor and both AFR sensors?
Do you have a life data scan tool? If so what is the long and short fuel trim of both banks reading?
How many miles are on this car?
Have you ruled out contaminated fuel or restricted fuel filter?
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Originally I had a problem with the engine "pulsing" during acceleration, so I had it looked at by a local mechanic. He immediately thought it was the AFM, so we tried it and it didn't help. With no codes present, we were stuped. My mechanic recommended I take it to Lexus for they would be able to run live data on the car. So I took it there and they jumped on the AFM idea as well (they thought they would have better luck with a Lexus part rather than the reman. one my mechanic tried).. I waited for five days for them to get the part in to try it and then gave up on them. I was wanting to drive the car to Florida that week, so I bought one from NAPA and had no improvements with that one either. When I got back, I took the car to another shop to have it looked at which has some pretty sharp mechanics. They too thought it was an AFM at first and ordered a Lexus one but the attempt was again unsuccessful. They ran some live data on the car and said that they'd found that the rear A/F sensor was bouncing back and forth between the high and low limits just shy of throwing a code. So they replaced that one and the pulsing was gone. However the engine still had the lean surges at low mph rolling starts and surges when starting from rest as well. So since the other A/F sensor was causing trouble and didn't throw a code, and this model is known for bad AFM and A/F sensors, and there was only one more of them to replace, I bought one from NAPA and installed it about a week ago. Initially it seemed a bit better but still seemed to shimmy and shake when accelerating at any speed.
I don't have a live data reading tool.
There are 40k miles on the car.
The fuel should be fine, I bought the car with this condition present at 34k assuming it would be a simple fix but I was wrong, so there has been a lot of good gas ran through it.
As for the fuel filter though it is a possibility I suppose. Is it in the tank or is it on the strut tower?.
With extremely low mileage is doubtful that the fuel filter is restricted unless you have put a lot of really garbage gas in the tank. Something like this is going to be extremely difficult to diagnose in this type of format where are you located? Are you anywhere near Cleveland? The only other thing I can think it would cause this problem would be injectors. This engine is known to go through a few injectors. The problem with this theory is though there should be a lean code set or a cylinder misfire code set. It is possible that you are slightly out of the thresholds for setting either of these codes. Without being able to see any kind of live data at cruise or during acceleration is difficult to say for certain. Let me know how you like to proceed.
I live south of Dayton, so I won't be able to bring the car to you. I suppose I will have to take the car back to Lexus and hope that they don't smoke me too bad. Maybe they will have better luck this time. I figured it would be difficult to get an accurate answer online to such a complex question with so many variables. Thank you for your help and time Mr. Miller.
You are weclcome. If you need a second opinion after the dealer vist just reply back to this post.