2000 S-10 Engine chugs, then dies

Back around March of this year, I noticed that my S-10 was chugging a little when I put in 3rd gear, but it never stalled out. I ran the tank nearly empty and added some fuel injector cleaner. Problem seemed to clear up. Then, however around the end of May, I had just left the gas station and noticed immediately that the engine seemed to have lost power. About the time I got home, it chugged a couple of times and then quit. Engine would turn over but would only run while I had my foot on the accelerator. This time I figured I had let the gas run too low and had gotten water in the gas. Put water remover in gas and proceeded to try to work it out. My dad removed the fuel line-fuel pump had plenty of pressure. After sitting overnight, truck cranked up and ran like a dream. Thought problem was solved. Then, a couple of days later, it chugged and quit. Again, it would run as long as I had accelorator pressed, but cut off on idle. Dropped off key at mechanic next morning. He reported to me that afternoon that it would not crank for him in my driveway, but after towing it less than a mile to his shop, it cranked like a dream. (I did end up having him to put in a clutch slave cylinder, but that was unrelated to the current problem).

He kept the truck for two days. He left it running for at least an hour at his shop with no problems. He drove it around town on a couple of occasions - he reported that it cut off once, but cranked right back up. Since check engine light never came on, he couldn't determine the problem, even after checking history. But, I've been driving it ever since without incident - until today. It chugged a couple of times in a parking lot and then stalled out. I turned off the key, sat for about 5 mins., cranked it up and came home - freaking out every time I stopped at a red light.

Even though I am boggled, I have a few hunches about what it might be, but this is where I need some expert advice.

Last Fall, I replaced the throttle position sensor (I believe that's what it was - a little round part with two bolts on each end that was fairly easy to replace). My truck was stalling at stops, but because the Check Engine Light came on, I we got a code. However, could that be the problem - is that part going bad again.

Also last fall, in the middle of deer season, I had to have the timing worked on - turned out to be a sheared pin on the cam shaft.

This truck is 3 months away from being paid for, it has 119,800 miles on it. I commute about 54 miles per day on it. Overall, it's been a good all around truck, but I have spent nearly $1,000 on it in less than a year. I may not be able to fix it, but I would love to at least steer the mechanic in the right direction if I have to drop it off.

So, Here are my hunches, but what do you think?

1) Throttle Position Sensor is going bad again?
2) Is something awry with the timing again?
3) Or, do my fuel injectors need to be cleaned/replaced?

By the way, truck had a tune up at 90,000 miles. Additionally, when engine cuts off, everything else runs fine - AC, Radio, etc - as if I had simply turned on the power before cranking the engine. What's really got me floored is that the problem isn't consistent. I may drive it for another month, and it won't act up.

Have any of you ever worked on or diagnosed a problem like this with a 2000 Chevrolet S-!0? I read another thread earlier that may be helpful, but it was an S-10 Blazer that wouldn't start back up. I'm starting to feel like Aaron Tippon, "Sometime she runs, sometimes she don't..." Please help. I'm a teacher, and we start school in a couple of weeks; I would really hate to end up spending all of the money I just made teaching summer school on my truck.:banghead:

Welcome to AF.
Any body that operates a vehicle will sooner or later have a break down.
They are mechanical and electrical and will break down.
But do not try to fit your problem to someone else’s problem.
It needs proper testing to find the problem.
First thing when it acts up find out if you are losing spark or fuel pressure or injector pulse.
What size engine does you have?
On yours I would suggest you hook up a fuel pressure gauge and tape it to windshield or outside mirror and drive it until it acts up and see if your are losing fuel pressure.

Post back you fuel pressure readings on cold start and engine idle and engine running on the road.
And pressure when it acts up.
MT

Where do I get a fuel pressure gauge? My dad may have one, but if not, how much am I looking at spending. When I had the timing fixed last year, the mechanic informed me that my truck - a 2000 S-10 with a 2.2 litre - was a flex fuel vehicle. He changed the fuel filter last November; the d**n thing was $85. Don't laugh, but what is the easiest way to hook up a fuel gauge? Do I connect it before the fuel filter or after it?

Most parts places have one you can buy or rent.
50-100 US dollars will buy one.
There is a test port scrader valve on the fuel line rail someplace.