I need some help. My '03 Toyota Tacoma 3.4L 5spd has been hesitating only during the summer months for the past 4 years. It now has 110,000 miles on it and it seems to happen on hot days after its rained. I'll go to take off from a stop and it seems like its starving for fuel/air/spark...whatever. I'll have the pedal floored and it will finally take off after like 5-10 seconds of lag. I won't let anybody else drive it because it's dangerous. Then when I shift to 2nd, it does it again. Of course it won't reproduce the hesitation in the presence of a mechanic. I've replaced the MAF sensor, fuel filter, air filter, spark plugs, wires, coils, cleaned throttle body and used Fuel Injector Cleaner. During the winter, no hesitation at all. It's more severe with the A/C, but still happens without. Toyota couldn't reproduce it either and it will not throw an engine code.
Has anybody experienced this? Any suggestions?