First let me start off with the engine 355 tpi in a 91 z28 Mods: superram, aftermarket heads, cam, 58mm tb, adjustable fpr, larger injectors, roller rockers, headers
The problem is the idle surges in park and neutral, dies in drive or any gear unless you work the gas, idle high and cant seem to set IAC and when i manage to or as close as i can it wont start unless you treat it like an old carbd truck working the gas pedal. Sometimes you even have to hold itat a high rpm for a minute to keep it running or to warm it up.
Also i have a prom programer and all the other tools needed to burn chips and i do use them in my car so if its programming i can change it just dont know what if anything needs to be changed in the prom or if its wiring or a sensor or part.

Here is what i have replaced since this started
ignition module
distributor
ignition coil
knock sensor
map sensor

every sensor and servo on my car has been replaced within the last two years

Im am completely stumped as to what this could be Any ideas?

 

How large are "larger injectors"?

What is the fuel pressure regulator set at?

 

They are 25 lb injectors and the fuel pressure was ok last time i checked it i just havent been able to since this problem started. My fuel pressure gauge is broke so i will pick one up tonight and post the readings.

 

Ok just checked the fuel pressure it roams around 40psi at a high idle but varies from 38- 42psi . I plugged the laptop in and it looks like the tps is working fine but the iac is going from 80-220 up and down with the surging. It making me a litttle worried . Im still stumped