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The car is acting like Fuel Starvation. When you give it full throttle it hardly will run. Checked the codes P1143-P1131 Came up. Changed the fuel filter-Spark Plugs. Good fuel pump. Replaced Timing belt & idler. I think it might be a sensor,what one? I would appreciate any help, Before it nickel & Dimes me
P1131 = Lack Of HO2S Switch - Sensor Indicates Lean
P1143 = Air Assist Control Valve Range/Performance
The first code indicates a problem with the O2 sensor (upstream, or the one before the catalytic converter) and the second code indicates a problem with the idle air control valve.
If the idle air control valve (IAC) is hanging open, the first code could be a symptom of that. Also, if the catalytic converter or the muffler is blocking the flow of exhaust it would cause a similar condition (since the IAC wouldn't be able to compensate). If the exhaust is being blocked, it would make more sense for it to be caused by the muffler, since a blockage across the catalytic converter would show a code for the upstream and downstream O2 sensor as well as the "Check Engine" light flashing while the engine ran.
It is very typical for an IAC valve to seize and also reasonably common for an O2 sensor to fail. You'd be doing yourself a favor if you test the EGR valve as well and make sure you don't have an exhaust system issue.