I have a problem with my 1990 5.0 if anyone can input that’ll be dope. I have a current stalling issue during idle. Around 10 mins my car would start to surge and finally stall. I have a t5, 306 w/ gt40 heads upper and lower gt40 intake manifolds, stock valves from stock 5.0 heads. B303 cam. Cold air intake, Stock exhaust with cats, replaced tfi from autozone, msd distributer, Amazon plug wires, motorcraft spark plugs and Amazon ignition coil . It has no smog pump nor egr , egr is sensor is bypassed. At idle I’m getting 14-15 on my wideband. Made sure to calibrate as well. I’ve done a tps reset base timing @10 degrees btdc. I have New tps iac spark plugs fuel injectors, fuel pump, good oil/fuel pressure @ 39psi, bottom end was fully rebuilt. Couldn’t find any vacuum leaks. Checked fuel and ignition system wires for resistance. I need of help.