Harlet3976

I'm new to this forum and just inherited a 2000 ES 300 Platinum edition that just hit 81,000. Been in my family since new and driven very little in the last 6 mos-1 year. I' replaced battery and front brakes, balanced and rotated tires and it drives really well. Issue is it has a bad lack of power at around 3500RPM and seems to surge from that point when passing. Had it on the highway for about 500 moles yesterday and the engine light came on throwing a PO171 code. Took it to Auto Zone and they recommended running some gum out through it to see if it would clean injectors. Prior to the light coming on I replaced the throttle position sensor, which did nothing. It also has a slight miss/delay if you hit the gas hard from an idle. I'm thinking about taking it to Lexus for a Injector service for $299. Not wanting to dump too much $$$ since I'll probably sell it. Sweet little car, but I know it can run much better. Read some old threads, but thought I would try and get some current information.

KevinES300

the most likely cause of P0171 and P0174 codes is a vacuum leak. The source of a vacuum leak can be one of many things. The most common cause of a vacuum leak is a leaky hose. Vacuum hoses over time can become dry and brittle. The rubber deteriorates and can leak causing a vacuum loss. Many times a leaky vacuum hose can be found by listening for a hissing sound. A large vacuum leak can even make the car run rough at idle. In some cases it will not idle without feathering the gas pedal. Another way to check for a vacuum leak is by using a Break cleaner bottle with the hose attachment. By introducing the cleaner to the area where the suspected leak is you can sometimes notice a change in the idle. This is this is the best way to check for Vacuum leaks and really works. then clean the throttle body and check you MAF sensor and clean it install a new air filter NOTHING is wrong with your injectors just too much air makes it think that the mixture is too lean use a bottle of high quality injector cleaner with high quality fuel and drive the car for few miles.
The results will take time.this whole fix will coast you about 15 bucks

Good luck

Harlet3976

I had the throttle body cleaned (if I can trust that source) and have put about 30 miles on it since filling up with premium and adding the injector cleaner. Can you actually clean the MAF sensor? A new one runs close to $200!

KevinES300

Check for intake leaks before everything; spry the break cleaner over every hose/around the EGR valve and under the main vacuum/MAF line try to wiggle them around during the process to make sure NO Leaks

KevinES300

And for your MAF Cleaning question do this:
All your need is a philips screwdriver and a $5 can of electric parts cleaner. you will notice the MAF sensor is located in the air filter housing. Just unscrew the two screws to the MAF sensor, unlink the power and you can see just how dirty the sensor is. Now that the sensor is disconected, DON'T TOUCH THE MAF SENSOR WIRES INSIDE! The sensor is very small and delicate. With the electric parts cleaner, just spray and let the dirt and grime disolve. I also found compressed air to be handy to help release the dirt after using the electric parts cleaner.

Once the part is clean, connect the power and screw in the sensor. You will have better power and acceleration, as well as the check engine light ready for reset. Just reset the ECU or delete the code from the ECU.

Harlet3976

Thanks Kevin. I can't find a leak and looked at my MAF and it loos spotless. Guess I could clean it anyway, but no signs of dirt. I'm wondering if investing the $299 for the full injector service is the ticket. anyone had success with that?

KevinES300

OK there are a couple more tests
first remove your easy to reach spark plugs and inspect them check for carbon buildup /Oil residue.
second unplug both of your Of your oxygen sensors and drive the car aggressively (Speed up fast) and put the transmission on ECT mode for about 5 miles and see if any thing changes in car performance.
last do a fuel pump pressure test after driving the car for a while (when the temperature of the pump is high because they might test normal when they are cold but when they heat up they start to malfunction.
good luck