Truck goes into gear slowly when its cold outside only. In the summer it goes into gear right away as soon as it gets cold out it shifts into gear real slowly. My truck is a S10 blazer.

Should get it checked out by a pro as you could burn something out.

Repair your vehicle right away. Just click on the link I attached Best Manuals

Has a fluid pressure leak ,could be a broken o ring.

Dirty fluid, clogged trans filter, Torque converter dirty. Shift solenoid sticking.

Taking the trans pan off and working on the filter and refilling the system would likely help.

It sounds like you need transmission fluid and filter change. This is one of the most overlooked maintenance items. It should be changed every 50k (30k if you tow a trailer) The delay in engaging gear is sign that trans fluid is tired or REALLY cold. In cold weather this is a normal symptom on cold morning starts but goes away when warm. I'd get it changed and soon, before it turns into a $$$ repair.

I doubt the two problems are connected. I would try a new gas cap and see what happens since it runs fine. The service engine soon light won't reset on it's own right away.

Many modern vehicles will delay the shift position to allow rpms to increase, thus warming the engine up faster. As soon as the engine temp reaches the desired level, the transmission shift point resorts to the normal point.

This is an emissions issue, with the idea that a warm engine puts out lower emissions. This is also why when getting an emissions inspection in states that require it, they want the engine warmed up first.

At 24K miles, I would be hesitant to say the transmission fluid and filter need to be changed, but if it seems extremely noticable and objectionable, that would be the step I would take. Cold fluid is more viscuos, harder to push thru a clogged filter than a clean one. However, unless you've been towing a trailer a good bit, your mileage should be low enough that filter should not be an issue.

CODE P500 VSS NO SIGNAL.PROBLEM COULD BE CONNECTOR TO VSS IS SHORTED OR THE MAGNET GEAR ON TRANSMISSION DRIVE SHAFT COULD BE BROKEN OR MISSING TEETH.

Try Pumping the Brake Pedal when it does this BEFORE you shift into Rev, or Drive.

Check the heat shield on the catylitic converter,exhaust manifold. Kev-Mn