Toyota Repair: Hard to start 96 tacoma, fuel pressure gauge, fuel pressure regulator

Question
My Tacoma, small 4-cyl, auto, 140k starts and runs Great until I've been running around town (stop & start) for a few hours in warm/hot weather. It then becomes harder to start, taking several tries to get it going. Sounds like it wants to go but doesn't, then it might just start instantly as if it were early morning. After sitting 30 minutes it fires right up. Gauge says temp is normal. Shop has replaced fuel filter, completely cleaned/depressurized induction and fuel system. Also replaced the fuel pressure regulator. (reduced fuel from 52 psi down to 40 psi. No improvement! Any help would be greatly appreciated. Thanks, Jeff

Answer
There may be a problem with one of the fuel injectors, it may be leaking fuel into the intake chamber after the engine is off, the best way to check this is to attach a fuel pressure gauge and see if there is an excessive pressure drop, there should be almost no drop in pressure even after a few hours.