Occasionally, the mass air flow sensor can go lean and set a code P0170 for fuel system lean. This in not an oxygen sensor problem. If there are no vacuum leaks, the mass air flow sensor may need to be replaced. Our technicians remind us to use a factory part because the aftermarket rebuilds are very inconsistent.
Check Engine Light With Code P0170 on Toyota 4Runner
Average mileage: 311,000 (311,000–311,000)
4 people reported this problem
2000 Toyota 4Runner 311,000 mi, Visitor
P0170 code was showing when tested, chcked for vacuum leaks and found a cracked vacuum hose, replaced and code was gone.