I have a 96 z28 I put in a 94 lt1 engine in it, I am using my 96 computer still to control it since i have obd2 emissions on it. The car takes like 10 turns to start, Finally starts, Then when driving and you punch it at around 4500 it starts to stumble and fall on its face pick up and does it again around 5200, Its like I am hitting rev limiter way early, What the hell is this, The engine didnt do it in the 94 z28 Cause I drove it before we parted it out, What do you guys think? I have no codes thrown for this. Thanks for any help, Also I had to use my 96 coil and stuff which was diffrent than the 94.

 

Sounds like the coil to me. My car did that it got harder and harder to crank and than when it hit high rpm's it didnt have enought spark to keep the rpms going. And than one day it just wouldnt crank anymore. Replace the coil.

 

Just replaced the coil tonight it was a little cruddy so I went ahead and did it, Same prob, Check for fuel pressure all is good on key on and start up, Fuel is good on fuel throttle no drop, This is pissing me off. Well more info i used my 96 manifold which I didnt know anything about which is the 96 map sensor, 96 injectors and rail regualtor, Which I know it isnt a fuel problem, Could maybe a map sensor cause this? Knock sensor? What? I didnt think a knock sensor would make it hard to start would it?

 

No the knock sensor should,nt be making it difficult to start.When i go to start my 94 z28 turn key to on ,count to 3(to prime fuel pump) and it usually starts.I have had to do this for years and i have the original coil and a MSD 6A IGNITION BOX as well. Hope this helps. 94 Z28

 

Yup I do that too. If I bump it a couple of times it will then start easy instead of just cranking on it.