When it's 80 degrees or above outside my check engine light will come on and go off and it will jerk. When it's cooler outside 70 or below it don't do it. Where do I start? It's a 1993 Ford F-150 4 wheel drive with 5.0 motor and automatic transmission.

 

You have the possibility of 2 problems. The easiest would be replacing the MAP sensor which can cause issues like yours. But I'd be more likely to be looking at the distributor. On the front of the distributor you will see a module, usually grey, that has the harness wired to it. This is called the TFI or Thick Film Ignition. These things will drive ya nutz trying to find a stumble as they work, then they don't, and it's all due to temperatures. It can be replaced without pulling the dizzy but if you are going to do it yerself, it's easiest to pull it. Ford had a major recall on those units and it covered engines to 1995. The recall has been over for years so Ford will be no help. Best of luck.

 

Thanks I'll try it.