[DeTomaso] NPC-1988 GMC Smog Test

[Art Stephens]

     I have a 1988 GMC 2500 3/4 ton pick up truck that has to be smog tested here in California this month.  Two years ago it only passed by the skin of it's teeth.  In the 15 mph Hydrocarbon test,  it blew 115 when 116 is allowable.  So,  I am pretty sure it is not going to pass this time.  My question is,  what can I replace to at least have a chance of passing?  I failed the hydrocarbon test four years ago and after replacing the catalytic converter,  I passed,  but not with flying colors.  The catalytic converter has about 50,000 miles on it and the EGR valve is six years old with about 80,000 miles on it.  The oxygen sensor is almost six years old with about 75,000 miles on it.  The engine is still running good after 282,000 miles.  I'm guessing that an engine rebuild would solve the hydrocarbon problem but of course,  I don't want to do that.  Any suggestions?

Thanks,
Art