Engine Performance problem
1997 GMC Jimmy 6 cyl Two Wheel Drive Automatic 98.000 miles
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I have a great truck on my hands that I have had many years and took exrta special care of through proper maintenance, and tune up's, oil changes...etc. But lately it has been running a little sluggish some days then running wonderfully other days. A few people have mentioned this sensor and said this could be the issue as to why it's so back and forth. After all these years the truck still gets decent gas mileage, and starts fine. No visible cracks in the distributor cap, plugs look clean I dunno.
I while back I had a friend hook a diagnosis machine up to it and a misfire popped up in cyl. 1, so I changed all the plus and wires- computer came up with nothing after.
Any input about this would be most appreciated.

i doubt its the tps. usually a tps is going to give you a code every time and they do not fail often in this truck, you are much more likely going to find a sticking injector or bad fuel pressure regulator.

well if your not getting any check engine lights , I don't think that your problem is your throttle position sensor, although it could be a little weak, there is not much you can do to determine that until it gets "week enough" and the light comes on. or you just replace it. what i suggest you do, is do a nice throttle bore and throttle plate cleaning and a nice decarb. with seafoam. you have to find someone that knows how to do a decarb though because its hard to explain and if you do it wrong you could hydrostatic lock your engine. what it does is removes all of the carbon build up on your pistons and valves. the whole top of the inner engine. its an awesome thing to witness because the carbon that emits from your tail pipe is unbelieveable. so just try that first, if you have the extra money to replace the throttle position sensor then go ahead. but other than that just go with the cleaning and try to find someone that knows how to do a decarb