I bought and drove car since Sept-2005. Absolutely No problems till May-2006.
Then it started showing P0171 but no problems while driving. Then it started vibrating mainly while starting in the morning and very rarely in afternoon again when I leave for lunch. But otherwise it runs sooth at any speed all the time on any road. I have taken it on long drives (500K Miles+) too.
I cleaned MAF sensor wires with CRC QD Electronic Cleaner couple of times, but it has not helped. When I took the car to Toyota dealer, He advised to replace the MAF sensor and both O2 sensors. But its costly affair $600+
Not sure what to do next? Is it related to Vacuum Lines leakage? Where can I check leakages in Vacuum Lines at reasonable cost? Or Should I replace MAF sensor first? Can someone Please Advice!