The IMRC solenoid operates your secondaries, so that might explain the secondaries not opening sometimes. The MAF fault may explain your other problem. Try cleaning the MAF sensor by removing the air filter and spraying electronic component cleaner down the sampling tube. The MAF is between the accordian tube and the air filter and has a 4 wire plug attached to the top of it. If this doesn't clear the MAF fault, it may be dead.
