Goood afternoon, welcome to JustAnswer!. This is Ed.
Rather than speculate just yet, I think the best thing would be to find out what codes are being stored in your PCM (engine controller) memory. When you have a CE light illumination while driving, you will have something stored and it's likely to be significant.
If you have a scan tool or can have someone scan the truck... great! This is by far the best way to find out what the specific code being stored actually is, but another (less accurate) way of pulling codes needs no scan tool. It's called the "flash method" and can be done in your driveway. We're going to do a quick key dance, then count flashes of the CE light without the engine running. It goes like this.
Hop in the truck and shut the door. Roll the key from off to on three times within five seconds, leaving the key ON after the last cycle. For those counting at home it goes OFF-ON-OFF-ON-OFF-ON (leave ON).
Watch the CHECK ENGINE lamp as it does a longer than normal "bulb test", eventually going dark. Get ready to start counting flashes.
Flashes will come in bunches, with short and long pauses in-between. Short pauses tell you to keep counting, longer pauses mean the previous digit is done (write it down). All codes are binary, having two digits (like 12, 22, etc), so when you're done, there should be an an even number of digits on your sheet. Code 5-5 will always be the last to be flashed, meaning this is the end of the test.
Feel free to repeat the test a few times to get the hang of it, or just get the truck scanned. The trouble with the flash method is that some codes (like 21 for oxygen sensor) can have several variants that are completely different in meaning, but since they include the oxygen sensor to some degree, they get lumped together because only so many flash codes can exist.
I'll stop there for now. Let me know what you find and the actual model year of your truck (or VIN, I can decode), because the 95 to 96 model year was a transition between OBD-1 to OBD-2, which is significant. A truck built in September of 95 is most likely a 96, but it does make quite a great deal of difference. If there is a great deal of backstory or you'd just rather do less typing, I'm available over the phone for a personal 1-on-1 to help sort things out.
Talk in a bit,