Is there anything that can cause a major drop in performance that will not be obivious? If you get no codes and car runs fine with no mechanical issues present. But when you put it on a dyno the numbers are down by 30%. What i am asking exactly is what could go wrong that might cause it and can it be diagnosed and fixed?

 

try cleaning your MAF

 

Valves adjusted ok? Valve springs still up for the task at hand?

 

Check for burnt plug wires. My car was doing the same thing. It seemed to run fine and everything, just didnt feel like it had the power that it once had. My 1/8th mile times dropped more then .5 and I couldn't figure out why. It idled fine, drove fine, shifted fine, just seemed like the power was breaking up high in the RPM's. I finally decided to check all my plug wires as I thought there wasnt a problem with them. Come to find out my #7 wire was burnt almost in half. I replaced the plug wire and bam, the power came back.

 

possibly o2's on there way out

 

My Ac Delco MAF arrived today (brand new for $90 on Ebay) so when it is installed i will see how it does after the install. I had the Granatelli on there and everyone said to go back to stock. The engine is completely stock. Can the valves go out of adjustment from 100K miles being on them? How do i check the valve springs to be sure they are doing there job correctly? O2's are almost brand new and i ran Freescan so all that seems good.

 

check your fuel pressure and see what its running at during idle and WOT. it wouldnt hurt to change your fuel filter also

 

Air Filter, Fuel filter

 

I ran several 0-60 times yesterday and got almost the same times each time. I could not break the tires loose on 5 tries. I installed the new factory MAF and pulled the Granatelli out and made several more runs. I had no traction on each run and was pretty close on times. I could not make a run without the rear end breaking loose. I got great times and averaged 4/10 of a second off my 0-60 time. I figured my 1/4 mile time would drop over a 1/2 second and if i had slicks would approach 13 flat. My old Maf was cleaned very recently so it must have been bad or because of the SC unit hurting performance. Back to the track for some revenge.