Ok, huh.....I just put a brand new LT1 in my 94 Z. Let me just list the mods to get them out of the way.

LT4 hot cam, Ported intake, Reprogramed PCM, Accel 30# injectors, Accel 300+ ignition, Pace setter shorty headers, K&N cold air ind., Flowmater cat back with no cat., New rebuilt 4L60E tranny, Transmision Specialties 2400 RPM converter, ATI inline fuel pump, 323 gears. Oh I'm also running a NX 150 shot (wet).

The problem is that the car just seems to shake and shutter...alot! The car feels like its missing under 2000 RPM. Whem I'm cruising at 50 to 70 mph the car shake or shutters, the more as i get into the gas until the tranny kicks down to a lower gear. It also kind of back fired through the intake a couple of times when I slammed the gas pedal from a dead stop. The car wants to pull at the higher RPM's but feels like something is holding it back. (basically just running like sh*t. I called the shop who reprogramed the PCM and they said they did everything right as far as the mods that I told them. I also called the summit tech line (where I got the injectors) to see if I went to big in flow rating. He said that I need an adjustable fuel pressure regulator to compensate for the bigger cam and injectors headers ec....I ordered one but have not recieved it yet. I'm not so sure that is going to solve my problem cause I have heard other members on the board using basically the same set up without the adjustable fuel pressure regulator. Does anyone see what I might be over looking? Did I go to big on the injectors? Do I need the regulator? Anyone?