Car looses the ability to accelerate while driving!

While driving my 2000 Nissan sentra GXE for at least 20 minutes (happens for some reason only on the highway) the car looses the ability to accelerate. I have to put the car in neutral and restart the car. This is scary and dangerous some how I managed not to get into an accident. I took the car to a local Nissan dealership. They claimed that they took the car out twice around 30 minutes each, and the car did not act up on them. When the dealership hooked the car up to the diagnostics they found a code for the engine over heat. The car never showed any signs of overheating. The dealership told me that the only thing that can think of was to change the thermostat as a precaution.

I drove the car after this repair and long and behold the car lost the ability to accelerate after 20 minutes of driving it on the highway and kept on happening about every 5 minutes.

Please help me with this problem!

the car lost the ability to accelerate after 20 minutes of driving it on the highway and kept on happening about every 5 minutes.

Could you provide a little more details? Exactly what is happening and how long does the event last? Since you say about every five minutes, does that mean it only last for like a minute and then returns to normal without any effort on your part? If you if you are not accelerating, is there any indication?

Has the curse control been on during these events?

Is the engine cooling fan coming on? How many miles on your Nissan? Has the water pump ever been replaced? Has there been any major service done to the engine in the last year? Have you owned it since it was new?

Has the cruse control been on during these events?

Ok, so it happens like this. I will be driving with my foot on the gas when I feel the loss in power. The first time I pulled off to the side of the road and as I slowed down the car would start to buck if i tried to use the gas. Even with my foot on the gas it still would not go over 1500 rpm. when I pulled over the problem would not go away until I restarted the car. After the first time it didn’t happen again for 3 more weeks but then it happened the same way. I could only get it to accelerate again after I turned the car off and restarted it. It happened again a couple days later and has done the same thing every time I drove it since then. It seems to be getting worse to the point it only takes 15 minutes to occur now and will do it again every few minutes after that. The only way I can fix it is to put the car in neutral and turn the car off and restart it going down the highway, unless I want to pull over every time. That was yesterday and I don’t want to drive it without getting it fixed due to safety issues. I never use cruise control and when the dealership looked at the car they said the cooling fans are coming on as designed. The car currently has 88,000 miles on it. The water pump has never been replaced (I really don’t think that overheating is the issue but the dealership said that the only code was on an engine overheat which never registers when i drive the car) There has been no major service on the engine ever and I have owned it since it was new.