The car is fully functional. There are no vacuum leaks that i or the shop have found, the z32 maf is working correctly, the car was professionally dyno tuned(tuned for 7psi) and inspected. The iacv and tps have been replaced. The car has all factory emission equipment installed and hooked up. I am not getting any CELs except when i unplug the top tps plug as described bellow.
The setup is as follows:
5-speed swapped 3 years ago with no problems or CELs since.
1996 KA24DE stock internals and head
jgs starter package with 50 trim agp turbo and 40mm jgs wastegate
walbro 255 fuel pump
emanage ultimate unit with boomslang harness
1996 OBDII CALIFORNIA model ECU(dont know if it makes any difference except for the fuel cut at 5500 RPM)
iridium ix spark plugs and new ngk wires
3 inch greddy downpipe, flowmaster 3inch high flow cat, and 85mm hks hi power cat back
(probably forgetting something)
Here is the problem, when i first start the car it idles fine for 20 to 45 seconds then it starts sputtering going down to 400-500 rpm range then bumping up to 1250-1500(the air/fuel ratio jumps around from 12,2-17.6), repeating this cycle once in a second. When the coolant gauge shows 120-130 the idle usually evens out(idle air/fuel ratio is set around 13.5). When i rev the engine it responds fine except for the fact that i cant hold the throttle at 1500-1750 because the car will die. When i release the throttle(after any kind of acceleration) the car starts sputtering for 6-10 cycles then it evens out. Also the car will not start properly when the coolant temp is above 120, i need to pump the accelerator for it to start up. Idle adjustments did not make much difference except for the fact that the rev ranges of the problem changed but the problem persisted. Now when i unplug the top plug on the tps the idle instantly evens out and the car runs and idles fine except for the fact that it runs rich when accelerating and on low throttle(when keeping the car at speed the fuel ratio is at 9.5-10.5 while it was at 14.6-14.9 when both tps plugs were in. when accelerating the ratio was at 14.6-14.9 with both plugs were in but with top plug removed the ratio starts off at 13.5 and decreases to about 11.7 at 4.5k rpm) .Also the car starts fine when cold or hot when the top plug is out. Any help would be appreciated.