IHAVE A 1991 JIMMY GMC I HAD TUNE IT UP PUT A NEW CAP AND ROTO PLUG AND WIRE AND CHANGE THE FUSE FILTER ALSO BUT IT KEEP CUP OFF WHEN I MAKE ACOMPLETE STOP AND WHE IAM RIDE WHAT COUL IT BE.

Nephew had similar problem on different vehicle - had spark to plugs, limited gas, everthing else checked. I did one thing first - check for two fuel filters - one in the tank was only screens and one in the line itself. Found a little in line filter just outside of engine compartment under car next to frame that looked like it had never been changed - partially clogged - replaced it.Almost ran but would not keep running. I had rotor and cap pulled - found that the screw holding rotor in place was loose. The rotor edge next to plug wire leads was chopped up and the cap's plug wire leads were heavily oxidized. Replaced them and got it running but a little rough. Pulled the spark plugs and found gaps from 25 - 100 ---replaced the plugs with correct gapping and it ran really well.

the mechanic may hav a plug wire on rong plug or the wires cud be old and they were pulled on--the distributer cap cud hav corrosion-chec it--inspect injector connections-mite hav been disturbed--fuel filter may be put in backwards--many techs dont test drive vehicles

Were you having these problems before the parts replacements, or only afterwards?

Try the ignition module located under the cap inside the distributor

YOU did the tune up? Check that the wires are in the right position, that the connection to the plug and distributor cap are good. Did you replace rotor and distributor cap? Wires could be needed. That wire might be bad

It depends on how many miles you have. A typical tune up would consist of changing transmission fluid, differential fluid, and engine oil. Also check the air filter, and oil filter. You should also check the serpentine belt for wear. You can change your spark plugs, but you will need to buy tools. Typically you would need to by a 3/8 size spark plug socket, a couple of extentions, and a ratchet. Make sure you change your plugs and wires one at a time, or you might put the wires in the wrong place. Your vehicle is new enough that it probably doesnt have a distributor (no rotor button or cap). But if it does, they are cheap to replace and I recommend doing while your at it. If you take your vehicle to a shop, double check anything they say is wrong. They will fudge and stretch the truth.

Try a major tune up (spark plugs are only one part of it) fuel/air filter, PCV valve, cap, rotor, spark plug wires and adjust timing..

if no codes possible needs a full tune up, plugs ,wires ,fuel filter, air filter

It sounds like you need a tune up, Spark plugs and wire and cap and rotor, fuel filter and clean the EGR Valve. I'ld say the EGR valve is dirty with carbon which is common in the 95 JIMMY"S and BLAZER"S which also means the throttle body needs to be sprayed down with throttle body cleaner, not carb cleaner since it's to corrosive to the gasket on the throttle body. Keep me posted, be glad to answer any questions you may have and good luck friend. 

a tune up would be the first step; plugs wires and fuel filter. then try a new rotor cap and button. if there still is a problem then check and see what you are getting for fuel pressure.