91 buick regal custom 3.1 engine had minor tune up now it runs rough and stalls after it warms up i ran a code search and came up with 0.pos. trottle position sensor or fuel injection or cat.converter?

Well, I am definitely not a mechanic but I can share my experience in hopes it may help. My 1996 Chevy Cavalier engine would stall frequently but then re-start after a minute or 2, only to stall again a few min later. The mechanics put it on the diagnostic machine to no avail. They then began replacing parts, wires & everything they could think of that would cause this problem without success. I replaced the gas cap & haven't had a stall since. The car runs like a charm. I don't know if thiswill help but my advice, for any auto problem, is to start looking for the small things. Hi .. I own a 91 Buick regal custom and I bought it from my father in law for $1 because of the same problem ... he rebuilt the top half of the engine tring to fix the problem ...when I first started it .. i knew .... you have to keep your foot on the gas and the brake to keep it running at a light .... its the Cat ... cut about one inch into your exsust pipe between the cat and the engine ...and she will never stall ..... its gonna be loud but .. if you have $60 you can put a new one on ....... the cats in buicks overheat and jam up or somthin... but it puts to much back presure on the engine and without having the gas pressed it won't hold idle .... so cut it and yes let it run VERY low on fuel and unscrew the gas cap .. if it doesnt make a presure sound like breathing in .... it needs a new cap too ... I have a 1989 Buick Regal and have a similar problem. When the car gets hot it has a rough idle and stalls mostly when in drive and stopped. If i put it in neutral won't stall but idles rough. I have replaced cat, several fuel injectors, fuel pump, fuel filter, plugs and wires and many other things in past being that it has 172000 miles. I still have the problem.