My van was running in failure mode today. The engine is running lean at about 290K with too little fuel and too much air. I’m thinking about installing new injectors. I installed new O2 sensors, new Mass Air Flow sensor and it actually idles better with the MAF disconnected. There is low voltage at the MAF. But a previous test showed it was OK. I am planning to install a new Idle Air Control and a distributor 351 Windsor. Do you have any suggestions for me?
I would first check voltage to the MAF - it should be 5 volts. Also check ground quality for the MAF. Since the fuel injection computer gets airflow volume data, a bad MAF reading will mis-instruct the injection computer. Also possible you have a bad "new" MAF, but more likely with this age and mileage to have a bad electrical path (corrosion, connector, bad ground, etc.). If the MAF tested with proper voltage earlier, walk back through what you touched since. Something changed! If you would like a certified technician from YourMechanic can assist you in diagnosis, and repairing the failed electrical components.
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