I just purchased a 1995 Z28 and could use some advise. The motor was recently rebuilt and it has about 1700 miles on it. Its a 350 LT1 bored out to 355ci with SBC Speed Pro Forged Pistons 30 over, forged rods, LT-4 hotcam, MSD Coil, Pace Setter long tube headers, 3 inch exhaust with gutted cats (I plan on installing a highflow cat) Flowmaster Muffler, stock throttle body, stock injectors, 160 degree thermostat. I am running all of this with the stock LT1 PCM. When I first bought the car and started it up in the morning it idled rough and wanted to stall. I just took the car for a 100 mile trip and now when I start it up it idles steady at about 2500 RPM. I know that it is going to need the computer re-programed but how to do it or what program specs to run I have no idea. I plan on using this car for an everyday driver. Any advise will be appreciated. Also, I live in So Cal (Redondo Beach) and if anybody knows of an inexpensive mechanic that specializes in these issues feel free to e mail me. Thanks

 

try going to pcmforless.com, they can tune your computer for fairly cheap.What kind of cam does it have ? If it has a real big one in it you may think it wants to die or stall but thats just how it sounds.Id also stay away from a flowmaster muffler, unless its their pro street single in single out race muffler.

 

With that work that has been put in bold, if you haven't tuned the car already you need to get a tune as Alih has suggested. Your computer is confused because you've made changes that it doesn't know about. Contact PCMforLess and they should be able to get you taken care of. If the car has been tuned it's a whole different story here.

 

do you know what kind of heads are on the engine ? an lt4 cam seems kinda small for a 355 build, usually people use an lt4 hot cam on a stock engine with stock heads

 

[&:]sideways it doesnt sound as though youve gone so wild on your build that the computer and its current programming that it shouldnt be able to handle it. id check for things like vacuum leaks and wheather or not the computer and all its sensors are up and running(does your check engine light function??) is there o2 sensors in the headers?? you need to verify these things before you even bother with a reprogram which may not even be needed. computer stuff is all or nothing. im not in cali so i cant help you with a tech but these should be stock problems and not something that requires a specialist in high performance computer tuning kurt

 

I am running stock heads. Thank you all for your help. t9ojetpilot you made a good point. I just bought the car and it seems like the previous owner Half A the electrical. I just bought a BBK throttle body and will install it tomorrow. I will go over the vacuum hoses to see if they are all sealed. Does anybody have a diagram of the vacuum hoses and where they all go. Which ones I should be looking for that would cause the car to run like that? This is my first Chevy. Thanks

 

i have a ? i bought a 96 z28 lt1 and the previous owner put in a different rear end 3.73 gears and neverreprogram the computer. the problem i am having with the car is that my car wont shift at wide open trottle. i have read 4L60e failure to upshift @ WOT and did the proper ajustments and i also had a trany tec at a shop close to me look at it to and it still wont shift at WOT. i just had the trany rebuilt. so i was wondering would reprograming the computer fix this problem

 

i would try that first, then go from there.