Truck has been running great since we last worked on it. Here recently at idle it acts as if it has a big loping cam, sometimes it does this and sometimes it doesn't. It drives fine, just when I first start or come to a light it acts this way. Sometimes I think it's going to die but so far it hasn't. There are no lights either on dash.

Most recent fix was a new updated spider assembly with fuel pressure regulator that came with it, even thou I replaced the original leaky regulator, we went ahead and used the one that came with the kit.

Where should I start?

 

Possible dirty passages in the throttle body & IAC motor? Maybe a vacuum leak somewhere? Might be worth a try.

 

What can make the TPS "break"? This is my 4th one, can something in the throttle body be messing it up? Does manufacturer make a difference? The first were cheapos from online, then I went with ones that were $35 each, but I see Delphi makes them which I think is the OE manu for $55. Should I go with them?

Truck is starting to do the same thing it did in the past so I know its the sensor again. Should I take the throttle body off and clean it, check it out, etc? Is there something else to replace behind the TPS that is causing them to fail? I see there is one way to put them on, I take my time, I didn't over tighten it, its nice and snug, the connector looks fine, that's about all I can do with it, pretty easy task to change.

BTW, the truck is stock, I don't mess with anything under the hood unless it needs to be fixed, no tweaking has been done.

 

The end of the throttle shaft looks like a "D". As long as the "flat" on the shaft lines up with the throttle sensor "D", there shouldn't be a problem. I've never seen it on the 4.3L, but if the bushing in the throttle body is worn, the sensor could bind up and break. Might be worth looking at when the sensor is off.

 

I found an image online, I will have to take a look. Will the throttle body need to be removed or can I remove and replace it?

Would you happen to have a part number for this bushing?

 

Uh, the image is a distributor, not the throttle body The bushing in the image comes with the distributor, it is not serviced separately. Same goes for the throttle shaft bushing, not serviced separately.

 

Guess I should have paid more attention

So you are saying I would need to buy a new throttle body?

 

IF that's the problem, (worn throttle shaft bushing) yes, it would require replacing the throttle body. Might be worthwhile checking with a boneyard for a good used one.

 

OK, you say "if"... what else should I be looking for?

 

It has to be something to do with either the sensor or the throttle shaft. You'll need to physically check it out.