Hi,
I am new to the forum and would appreciate any help I get with this problem. I have had a '97 F150 with 4.6 for about 2 years now. A couple of weeks ago we had a cold snap here and this problem popped up. After idling for about 5 minutes, the add oil light comes on and the temp gauge pegs Hot. Shortly after, the check engine light came on. I had it checked by a local mechanic shop and they read the codes and said the mass air flow sensor needed to be cleaned. They did that and I went on my way. Well about 5 minutes after that on the way home it did the same thing. It has done the same thing several times since then. When I turn the engine off, the gauges go back to normal and after awhile the check engine light goes off. The engine really loses power when this happens and runs rough. When I turn it off and on, the engine runs OK. Any ideas?

 

You may have air in your coolant system. An air bubble can move through the system as it passes or stops at the temp sender the sender spikes the gauge. It may also be triggering the failsafe/limp home mode causing the truck to run rough. Not sure why it just started but I would check the coolant level in the radiator degas bottle. You may have to purge the system to get the air out. It could be something else causing this as well but I would check here first. Good luck. Just had another thought. You said it just turned cold in your area. Do you have a mix of antifreeze and water (50/50)or are you running a weak mixture with a higher water content? If it gets cold enough you could be getting ice in the cooling system which would restrict flow until it warmed up enough. Long shot but I know of people who bought used cars that had all water in the coolant system.

 

I am running a 50/50 blend of antifreeze/water. I live in Western Iowa. By a cold snap, I mean around zero. Someone else thought it was a bad temp sensor. That is a good idea though, if it is just sensing air instead of coolant.

 

Could be the bobble of air, or as somebody suggested you a bad temp sensor, sounds to me that your engine is going into failsafe; I had a misfire on my truck a few weeks ago due to bad spark plug wires, and that misfire was on one cylinder and I could feel a lost of power and very rough idling, when you go into failsafe it's my understanding that your engine runs on 4 cylinders which should be pretty obvious and a bigger lost of power