Have a 99 4Runner SR5. Check engine light came on about a month ago and I had my shop scan it. It had a code PO171 which is a lean code. We replaced the MAF sensor and it solved the problem of the check engine light and it dogging out under acceleration. Now it revs itself up and drops during idle. Thinking about replacing the IAC too. It is a 5 speed manual transmission. Was wondering if anyone else has had this problem?