Can an EGR valve not working properly cause this problem?

[kwren]

A problem with some person from Dallas Texas says he can be driving along for several miles and all of a sudden his water temp goes way up, the air conditioner stops working. The temperature comes back down and the air conditioner starts working again. This would seesaw back and forth a few times, but at other times it doesn't happen at all. Not a coolant leak and fans are working properly.

My car has been running real bad with the check engine light coming on after sometimes a mile, and at other times maybe 25 miles before the check engine light would come on. It seems to come on quicker when I am not pushing the car a little too hard. Translation... (When my wife is riding with me. )

Yesterday on a 90 degree day up and down hills about 65-70+ mph my car started the temp rise a ways and then after a few minutes, not many, the temperature would drop back down to normal… each time this happened, the air conditioner fan kept blowing air, but the cooling stopped. Higher rpm in a lower gear would bring temp down and the air conditioning cooling automatically would just happen. Did it about 3-4 times the same way.

The EGR valve re-circulates exhaust gases into the throttle body to decrease combustion temperature and thereby reduce NOx and improve fuel consumption

My question is... Can a defective EGR valve cause combustion temperature to increase enough while not preventing the NOx, which could also cause excessive temperature, result in rough running and at times a rise in coolant temperature?

Getting up to normal temperature is pretty much a prerequisite for the rough running and check engine light to occur... on our SVX.

We need a break on this rough running, ck engine light, and up-down coolant temperature problem.

All input appreciated…

Keith... always