Lexus Rx300 P0171 Error Codes Replaced Ignition Coil/plugs

[NiaSemaj]

Prior to this I have recently had a new battery and alternator put in within the past month.

I took my wehicle (1999 RX300, mileage around 143,000) in to a local Quiet Zone due to the Check Engine Light Blinking and the car would not accelerate above 20 mph. They said there was an exhaust leak and wrote up an estimate for the exhaust work around $220. When I asked if that would resolve the lack of acceleration issue they said, no they can perform a diagnostic test, which I paid $70 for and did not get a print out - they wrote it on paper.

They listed: 99 Lexus - RX300: gaskets, converters, plugs, ignition coils Total: $3285.89

The serviceman said that it could possibly be the fuel injector but they did not put any of this in writing. They provided no codes or anything. Later after my father asking me about the codes, I called and spoke to the receptionist and she stated their diagnostic computer doesn't print out. The only reason I went there is due to word of mouth referral.

I then went to Autozone, who ran a test and the following codes came up: P0171, P0300, P0301, P0302, P0303, P0304, P0306.

I had all six ignition coils and all six spark plugs replaced - spark plugs 2, 4, 6 were black/corroded compared to spark plugs 1, 3, 5. The check engine light is no longer on. I put a half tank of 93 fuel and the car is running and much better at accelerating, but there are still some exhaust fumes. We noticed that there is water leaking near the rear passenger tire.

My concern is based on the trip to Quiet Zone and the lack of information they provided me. its causing me to mistrust anyone giving an estimate or where else to go. The Lexus dealership wants $122/hour to do diagnostic tests.

Help!