Well to start, I currently have a 1993 hatch that is a vx. It has a stock ls bottom end, with a b16 head, gsr cams, arp headstuds, and a ls headgasket. It has a stock 2000 si intake mainfold with stock injectors, tb...you get the deal.
HERE IS THE PROBLEM: I was at a gas station, my buddy went inside and when he came out, got into the car...the car idled at 2000 rpms. So I suspected (since I didnt move) the ecu took a dump, or the wiring (since it was mangled).
So I went and got a used (but virgin) cabin wiring harness and engine harness. When everything was plugged in the car wouldnt even start. I changed the engine harness back to the vx harness, and the car started up first try and idled like a dream...right at 1000 rpms (what I wanted it tuned to on the ecu). I took it out on a run and it drove fine, then after a couple hours (not straight driving) it randomly started idling high and went into limp mode not going over 4k and getting 30 miles per tank
Now I suspected since the cabin harness because it was not wired for vtec nor the ecu. I checked the wires (via a ~5V voltaic battery thing) and found all sensors were wired correctly except the IAC (and of course VTEC...etc.). I wired the O2 sensor, Vtec wires, and the IAC straight from the wiring on the ecu. When I started up my car it now sounds like a V8, misses constantly (just from reving the engine).
I just really have ran out of any other ideas besides a blown headgasket...I have changed the IAC (ran worse), changed the tb to a 70mm one with new sensors (idled at 3000), checked for vacuum leaks, etc. Right now when the IAC gets disconnected, the engine wont idle and has to be held, but it loses the "V8 sound." My car is tainted...really any ideas that I can try would be helpful!
P.s. Sorry for the paragraph, but so many people are descriptive when describing their problems....