Toyota Repair: 99 Avalon sputtering on deceleration and idle, p0171 system too lean bank 1, cylinder misfire

Question
QUESTION: Recently my Avalon as begun sputtering upon deceleration and at idle. It just recently topped the 100K miles mark. It had happened in the past once or twice, but it is now more frequent.  Today the check engine light came on while on a short trip to home depot, and then on the return trip home the traction control light came on.  I was wondering if the sputtering might have to do with an oxygen sensor, but I don't know what the traction control has to do with that...maybe nothing I guess.

ANSWER: It's probably an engine misfire, the first thing is to get the trouble codes, locate an Autozone store if possible, they will get the diagnostic information for you, write the code numbers down I will need them when you reply. The VSC/ TRAC lights will turn on whenever the check engine light is on, there is probably nothing wrong with those systems and these codes clear when the problem is fixed and the codes cleared.

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QUESTION: Ok, the codes were P0300 Random/Multiple cylinder misfire...and P0171 System too Lean (Bank 1).

Answer
The p0300 code is not specific to any single cylinder but it affects all cylinders so there is a problem that is common to all of the cylinders, the p0171 lean code can be caused by an intake system air leak, all the vacuum hoses an the intake chamber and the air filter should be checked to see if any are leaking or disconnected as well as the large intake hose that connects the throttle body to the air filter.