I've seen that truck before. One thing you should do is change the timing belts. There probably old and have never been replaced. Do it now before it makes you do it when you you can least afford to be down. We have seen this happen many times. A new owner gets the truck then bam. Broken parts and big problems.. Another good thing to do is clean all the ground connections. The truck is 23 years old now, and this is when things really need to be looked at cleaned and protected. If there are things that are jerry rigged in the electrical then it is a problem just weighting to happen. Since you passed SMOG so easily then NOW is the time to take action. Preventive Maintenance is the key.