I HAVE 96 BLAZER with codes p1380,p0300 and p0303 ,i replace rotor,cap rotor,spark plugs and wires and codes stil there and have good cold start,no smog of any color but have a strong vibration what i can do to have it run even or smooth please some one help thanks. i already use $1500 in parts i don't want to spend more if no necessary.

 

*Moved to '2nd Gen Tech'*

 

fuel pressure test, check fuel pressure and leakdown. You want it to come up to 60psi and stay above 55psi for at least 10 min.