Alright my car is a 91 z28, 5.0, 5 speed(121,000 miles). I took it to get it smoged about a month of ago and it didnt pass, so i took it to get a tune up and the guy said that the timing is real high and he brought it back down to stock. After he did that the car seem to run real slow and no power in the powerband(i know that having the idle up adds power thats why i had it like that) but it did pass smog this way. So then today i went to put on my feul pressure regulator that i got and while i was at it i was going to boost the timing up. I put it on moved the psi up to 46 and adjusted the timing a little to 8 degrees but it is still lacking A LOT of power. To me just 4 degrees of timing can't give me like 30 more hp so i was wondering if anyone would have an idea of what it can be. Do you think that the guy when he was tunning it messed up a vacuum line or somthing. Any imput would be greatly appreciated cause i am at a big loss, thanks.