New here and thanks for the info already
 

What's up guys. I'm new to the forums but I've been reading info here for a couple of months, alot of great info! I want to see if you guys can point me n the right direction. I bought myself a 97 f150 ext cab 4.6L engine. It was running descent when I got it, but I changed the alternator, tensioner, idler pulley, water pump, fan clutch and top and bottom coolant hoses. Here's my issue, today on my way home from work I noticed the temp guage pegged and the oil pressure light was on but the truck was still running fine. now this is where I'm lost, when I pulled over and shut off the truck I checked under the hood the reservoir was still at level, the oil dips tick reading was good. I started it back up and everything was normal, no oil pressure light and my temp was right in the middle of the guage again. I like toying around and fixing my truck up but this may be out of my range of knowledge. Any feedback will be greatly appreciated.

It can be a variety of things causing the issue. The dash comes with a voltage regulator that sometimes goes whacko and gives false readings. The alternator could have surged the system causing high voltage and the false readings. PCM may be the issue along with a bad battery. Some times the electrical gremlins can lead you on a merry chase to find the cause. It may never happen again and then it could get worse. Best of luck trying to figure it out.

Thanks so much for the info. So far it hasnt happened again,

Issue found
 

Hopefully this info may help someone else. My truck did it again and started to do it more often. I changed out the CHT sensor( cylinder head temp sensor)https://cimg7.ibsrv.net/gimg/www.f15...29982d8b29.jpg