P0171 2006 Chevrolet Trail Blazer - short term fuel trim3 is at -88.3 %

Question

Replaced o2 sensor, MAF sensor, A.I.R check valve,
Even replaced gas cap Still getting p0171 code
2006 4.2 liter I6

Answer 1

Hi there,

This could be caused by leaking intake manifold gaskets or exhaust gaskets. Low fuel pressure as well or even the valves being out of adjustment.