1999 buick regal codep0305

code p0102 refers to MAF/VAF sensor ---low input ===causes --wiring short to ground. MAF/VAF sensor
code po172 refers to system too rich --bank 1=== causes ---intake blocked --EVAP canister purge valve---fuel pressure ---HO2S sensor
code po random misfires ---plugs --wiring ---injectors--low compression
code po305 refers to cylinder 5 misfire detected ===causes --engine mechanical fault--ignition/ fuel system ---injector ---ECT/MAF

I would check that the air filter is not blocked first as it affects the MAF/VAF sensors . Have a fuel pressure system pressure test done

Change distributor cap and rotor then check your timing. Hope this helps. Good luck. =-)

# 3 cylinder misfire (PO303) if code is
actually correct for your problem,nothing
to do with spark plugs,ignition problem

these indicate a misfire on cylinders 2 and 5 the code 300 is random misfire.does the car need a tune-up plug,wires, the fuel injection system need cleaning,also there could be a intake vacuum leak with the intake gasket leaking causing the misfire near these cylinders.

Its possible the crank sensor is going bad,easy to replace and cost under $30. remove one plug and one bolt .

These are cylinder misfire codes meaning ;
P-0300 = RANDOM OR MULTIPLE MISFIRE
P-0302 =CYLINDER #2 MISFIRE
P-0305 =CYLINDER #5 MISFIRE
Check spark plugs, wires, and coil(s)

These are misfire codes.This means that your vehicle is missing.The 300 is a random misfire and the 305 is for cylinder 5,and the 306 is for cylinder number 6.Check the plugs if they are good then you could have bad coils.They are top of the plugs.Hope this helps.Good luck.

possibly oxygen sensor/s?

the light is flashing to tell u that the engione has one or more engine cylinders misfiring, have the trouble codes tested to find out which cylinder(ws) is he problem.

Hey Dan, It cannot hurt to change the Plugs and wires. Make sure and Check all the Fuses and Relays also. Sometimes the Realays can blow or just get old and send a Code also.