QuestionTrouble codes P1128, p0300, p0301, p0302, p0135. Have changed the fuel filter , fuel pump, plugs, plug wires, front o2 sensor. The car starts and idles fine, when you start to go the car hesitates and doesn't have much power.Sometimes during acceleration the engine light flashes. any help please
AnswerP0300, P0301, and P0302 (multiple misfire, misfire cylinders 1 and 2) together with the P1128 (lean condition under load) lead me to believe you may have a fuel pressure problem. Start with checking your fuel pressure. According to the shop manual, you should have 50PSI fuel pressure. That may be a little high. If you have anything under 35PSI, the fuel pump definitely needs to be replaced. If the fuel pressure drops significantly when you accelerate, the fuel pump needs to be replaced.
If you have good fuel pressure, then you probably have two separate issues relating to the above codes. For the P1128, if there are no vacuum leaks (check especially the PCV hose), you probably need a new air flow sensor. For the P030x codes, you'll need to diagnose the misfire. Start with checking the plugs, wires, and coil, as these are the most frequent culprits for misfire problems.
P0135 indicates a problem with the heater control circuit of the front oxygen sensor. In most cases, this is caused by the oxygen sensor itself.
