What could be the cause of my car all the sudden not accelerating, instead only revving up & the thermostat went all the way hot when the vehicle was no where near hot?

SOURCE: Yesterday my wife was driving our 2006 Nissan

Solinoid sticking.Maybe a one off thing.I wouldnt worrie about it unless it keeps happenig

SOURCE: Over-revving in 5th at 75mph all of a sudden

If the car rev'd up but did not speed up at the same time the clutch is starting to slip. Check the adjustment and recheck driving. When the clutch starts to wear this is how they act, only most people ignore whats happening and keep driving till adjustments won't fix it and the clutch has to be replaced. Have adjustment checked and keep an eye on it and hopefullty you won't need a clutch yet.

Testimonial: "thanks for responding so quickly, thank you :)"

SOURCE: Vehicle revvs without acceleration, may be leaking oil and tranny

You have most likely poked holes in the oil pans for the engine and transmission, or oil lines for them. You will have to go under the truck with some rags and start wiping things off looking for dents and or holes. Leaks will oil back up quickly when you wipe them off. If you see puddles of oil under the truck start there. You are probably looking at replacing these pans and lines which wouldn't be too expensive but you could also be looking at replacing the transif it has burnt out. Check the fluid level and for color and smell. If the trans fluid is brown or black and smells burnt you will have to change it. A scrap yard will be your best betfor another trans, $500 or so depending on the yard. Get some skid plates if you are going to keep on off-roading. Hope this helps.

SOURCE: When accelerating, the car jerks and hops and pops

SOUND LIKE PROBLEMS WITH EGR VALVE.ITS NOT WORKING.

SOURCE: 2001 Saturn LW200 engine revving

It may be something that only happens when the cars is driven for a while. They need to test drive the car and try to duplicate the conditions when the revving took place, such as what speed were you driving at the time, were you accelerating or cruising at a steady speed, was the cruise control in use. I'll try to research the problem to see if it is a common occurrence with your vehicle model.