Oil not gettng to valves

I have an 86 gt with a 2.8 and ive had this problem since I bought it but it ran fairly normal except for a slight ticking sound at idle.  I replaced the stock oil pump with the HO one but still no luck. Ive also tryed both 5w30 ad 10w30 but still no luck. Anyone know whats going on with my engine. The prevous owner had it sitting for over a year could this have clogged something?

Have you considered it could be a valve out of adjustment or a simply bad lifter?

I can't count the amount of Fiero's I have heard or seen that had the valves adjusted incorrectly. I have even screwed it up a few times and I have more experience working on Fiero's that 90% of the population.   The main problem with changing lifters is the odds that the old cam won't lose a lobe are about 50/50. You can take the top end of the motor off, get the rockers, re-set the rockers and use new rocker arm nuts. That might solve your problem. If it doesn't, you may have to pull the engine, swap the cam and lifters as a unit.   If you get to that point, its worthwhile doing a light rebuild on the motor. New bearings, new rings....    Or just live with the clack until it dies. My 88GT has had a clack since I bought it. I quickly found a spare motor for it in preparation for that clack to go boom. That was 40,000 kms ago and 4 years. I think it is just the engine talking to itself and it must make it happy, cause it starts every day, and got Lisa and I to and from Vegas in 2007.

Yep it is a fair bit of work. I guess it would depend on how good or bad your current engine is. Does it burn oil, have you done a compression test. What are the results? If you have a good bottom end then it is worth fixing the lifter noise. However if you are burning oil and have bad compression then changing it is a good idea. I have had mixed results with used engines. Some installed and ran for years, others installed and I was lucky to get 12 months before they let go. Any un-rebuilt Fiero V6 is 20+ years old now. No one really knows the entire history on a motor so the best you can do is try to find out how good or bad it is and go from there.