Pontiac Repair: 95 pontiac grand am 2.3, mass airflow sensor, vacuum leak

Question
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Followup To
Question - hi there.  what are the quad drivers and the engine has been rebiult   thanks for anwsering
i'm having a problem with my car. it started misfiring, spuddering and smoking smells like gas coming from exhaust. gets so strong it burns my eyes  when driving it. it runs great when its cold.  10  to 30 minutes later it starts running bad. it misfires the most when i am just cruising and idling. i smash the thottle and it comes out of it. i replaced the injecters, coil assembly 2 times, spark plugs, thottle position sensor, computer 2 times, fuel regulator and map sensor. still did not correct the problem. i bought a scanners pluged it in. scanned for codes.  it found 2 problems. a injector circuit problem and low voltage in map sensor.  on the scanner it showed all the read outs on the sensors. i  seen that there are 4 quad drivers that read out bad. what does this all mean and how can i fix my car. i am so fed up with it i am ready to call the junk yard. help please.
Answer -
the oxygen sensor tells the computer how much fuel to give the engine.the mass airflow sensor tells the engine how much air is coming in the engine i would check these.youve done just about everything else.there could also be a vacuum leak these usually get worse as the car warms up.i would also do a compression check on the cylinders.i have seen a bad cylinder<broken ring or cracked piston>throw everything out of wack due to low compression.  

Answer
you should get a repair manual for your particular vehicle.it should have all the codes and explanations.im not sure what the quad drivers are but the manual might help.if the engine has just been rebuilt and is giving problems there might be a timing problem.