From what you are explaining sound like it may be a leak in the plenum. I know you said you replaced it. Did that make difference or did it act the same? Well it could be the crank or cam sensor. What brand sensore did you use? Mine didn't act up until you drove it about 15-20 minuets so temp effects the sensors. The pcm need constant inputs from both of them. If it cuts out or doesn't see an input it doesn't fire the coil. Engine needs to make one complete rotation before it fires again.

 

Mine does the same drives good for 30 mins tgen starts running horrible. I believe the sensors are either Mopar or standard brand. I guess it could be the crank sensor again because it contour the tac and if it went to zero while idle and then back up that's the only thing that can explain that. What causes that to go out?

 

Crank sensor is just a hall-effect switch.. you would think it would be a simple matter to make them pretty reliable... but, that doesn't seem to be the case....

That said, I have an SMP sensor in my truck, been there for a couple years, and seems to be doing ok....... luck of the draw?

 

I don't trust the junk the parts stores sell. Mine is a perfect example. No one around me sells Delphi sensors. And if they do it's $$$. So after the one from pep boys acted up i ordered a Delphi from rockauto. It's been in about 4 years and no issues.

 

I need to replace my crank and cam sensors again but there not cheap and it's still just a guess. I replace the plugs and wires yesterday and it drives better but didn't fix the problem.

 

Start with the cam sensor. It's easier to get to, and less expensive.

 

i havent been able to change the crank or cam sensors yet. i have changed the spark plugs and wire and cleaned the trottle body and the truck drives smoother but still jerks. It has a weird symptom; while driving the tac will jump up 300-400 rpm and then drop 300-400 rpm and will even drop to 200 rpm and if i give a little gas it will pick back up and drive better.

 

Got a call from the shop my whole distributor is bad. What could cause the distributor to go bad?

 

Shaft bushings? That's about the only thing I can think of...... and that's RARE. How many miles on the truck?

 

170k on it. I was quoted 350 for the job if that's all that's wrong. Is it likely that will fix the problem or do you think it will be the inside of the engine?