HI, this is my first post as i am new to this forum. I have a 97 t100 that is having an issue starting when it gets hot outside. it fires up perfectly on cooler days, and in the mornings. but when it get over 75-80 degrees outside, it will sit there and crank for about 10 seconds or so, then eventually fire up. it almost seems like the fuel is evaporating. It runs good and doesn't seem to have any power loss. I changed the fuel filter but that didn't take care of it. I'm leaning toward replacing the fuel pump, but not quite sure yet if i should since it runs so good still. any opinions on this situation would be much appreciated, thank you.

 

How many miles?

Have you checked the IAC valve?

How gunked up is the throttle body?

When was the last time you cleaned the MAF and reset the ECU?

 

I'm new here too, but I've had that problem for years on my '97, T100, 6-cyl with 82K miles. It's always the most troublesome during the warmer months when the temps rise 25-35 degrees from morning, when the truck starts easy, to late afternoon, when it takes a LOT of cranking to fire. But as soon as it fires, it runs fine. I had the truck at the local Toyota shop for some other work, but they couldn't find anything wrong. Since that time I've found that there is a lot of vapor pressure build up in the fuel tank on those hot afternoons. If I loosen the fuel cap a little in the morning, the problem is almost non-existent in the afternoon. I'm no mechanic, but this high level of vapor pressure build up in the fuel tank seems abnormal to me... my other vehicles don't do that.