Poor starting, rough idle, and sometimes "chugging", 96 Jimmy

I have a 1996 GMC Jimmy with around 126K miles. I bought it used about 2 months ago, and began noticing problems a few weeks after purchase. After putting a bottle of fuel system cleaner in, I noticed difficulty in starting the motor. The motor has always started and never left me stranded, but it began starting on the second or thir attempts. One day while driving home from work, at around 65 mph, the motor began “chugging” and almost bucking while I attempted to accelerate and the check engine light came on, and stayed on til the next morning, and then it shut itself off(the light). I have not changed spark plugs, fuel filters, or anything outside an oil change. What could be my problem?

The problem could be any number of things. Do you have any idea when the plugs/wires & filters were last done? If you don’t then you should just do them.

If the check engine light comes back on go to a chain-type auto parts store & have the codes read. Write down the exact code(s) and post.

Do all the regular maintenance stuff, especially fuel filter. Then see if you still have a problem.